DIGIPLEXER FMX410 USER MANUEL

Transcription

1 DIGIPLEXER FMX410 USER MANUEL Issue : 08/07 Language : English AUDEMAT-AZTEC and Navigator are registered trademarks of AUDEMAT-AZTEC Company. Page 1 sur 87

2 SUMMARY BEFORE STARTING... 5 INTRODUCTION... 6 WHY "DIGIPLEXER"?... 6 YOU HAVE JUST ACQUIRED AN FMX410 OR FMX440 DIGIPLEXER... 6 FMX410 DIGIPLEXER GENERAL SPECIFICATIONS PHYSICAL COMPONENTS AND INTERFACES THE DIGIPLEXER CASE REAR PANEL FRONT PANEL INTERNAL COMPOSITION OF THE DIGIPLEXER FMX410 PCB : JUMPERS, POINTS OF ADJUSTMENT SCHEMATIC ABOUT THE COMPOSITE MULTIPLEX SIGNAL ABOUT THE COMPOSITE MULTIPLEX SIGNAL MULTIPLEX SIGNAL COMPOSITION LEVELS AND UNITS USED TO DESCRIBE THE MULTIPLEX SIGNAL PRINCIPLES OF DIGITAL SYNTHESIS OF THE MULTIPLEX COMPOSITE SIGNAL ADVANTAGES OF GLOBAL DIGITAL SYNTHESIS OF THE MULTIPLEX SIGNAL INSTANTANEOUS DEVIATION AND POWER RELATED TO MODULATION THE "MULTIPLEX LIMITER " OR " MULTIPLEX CLIPPER " FUNCTION AGC FUNCTION "ADDPWR" FUNCTION THE MPX LIMITER POWER FUNCTION Description of the new commands Activation of the MPX Power Limiter Example of procedure for using the FMX410 limiter SUB-CARRIER DEVIATION EFFECT OF THE SUB-CARRIER DEVIATION ON THE GLOBAL DEVIATION THE IMPORTANCE OF SUB-CARRIER SYNCHRONISATION DIGIPLEXER INSTALLATION AND USER S GUIDE POWER SUPPLY GENERAL INSTALLATION LAYOUT OF THE EQUIPMENT WHERE TO CONNECT THE INCOMING AUDIO SIGNAL, LEFT, RIGHT? WHERE TO CONNECT THE MPX OUTPUT OF THE DIGIPLEXER UNDERSTANDING AND CHOOSING THE «BYPASS» FUNCTION INSTALLATION OF THE DIGIPLEXER WITH AN EXTERNAL RDS ENCODER INSTALLATION OF THE DIGIPLEXER WITH AN EXTERNAL STEREOPHONIC ENCODER INSTALLATION OF THE DIGIPLEXER WITH AN EXTERNAL COMPOSITE LIMITER INSTALLATION OF THE DIGIPLEXER AS AN EMERGENCY BACKUP TO EXISTING EQUIPMENT TO CONNECT EMERGENCY BACKUP EQUIPMENT TO THE DIGIPLEXER TO USE THE MPX INPUT FOR THE INSERTION OF AN SCA OR ADDITIONAL SIGNAL TO SYNCHRONISE THE DIGIPLEXER BY AN EXTERNAL CLOCK (19 KHZ) TO RECOVER THE DIGIPLEXER CLOCK REFERENCE (19KHZ) Page 2 sur 87

3 TO ADJUST THE NOMINAL SENSITIVITY OF THE DIGIPLEXER AUDIO INPUTS TO ADJUST THE NOMINAL OUTPUT LEVEL (LVLO) OF THE DIGIPLEXER REMINDERS ON THE PRE-EMPHASIS FUNCTION MONOPHONIC TRANSMISSION STEREOPHONIC TRANSMISSION TO TRANSMIT THE TEST SIGNALS MULTIPLEX PROCESSOR OPERATION (AGC, CLIP, ADDPWR, SEFFECT) TO MODIFY THE CUT OFF FREQUENCIES ON THE AUDIO TRACKS (L+R) ET (L-R) TO SAVE THE CURRENT CONFIGURATION IN USER MEMORY TO USE THE CONFIGURATION IN USER MEMORY FOR TRANSMISSION TO RESTRICT ACCESS TO THE DIGIPLEXER PARAMETERS TO PERSONALISE THE WELCOME MESSAGE OF THE DIGIPLEXER (FRONT PANEL) TO USE THE DIGIPLEXER WITH A MODEM TO DISPLAY THE COMPOSITE MULTIPLEX OUTPUT LEVEL TO DISPLAY THE PREDICTED DEVIATION (MULTIPLEX SIGNAL) ON PC TO DISPLAY THE PREDICTED POWER (MULTIPLEX SIGNAL) ON PC TO DISPLAY THE ACTION OF THE AGC FUNCTION AUTOMATICAL PROCEDURE FOR THE ANALOGUE INPUTS CALIBRATION TO USE THE FRONT PANEL TO USE THE DISPLAY AND THE "SEL" AND "OK" BUTTONS WELCOME MESSAGES ON THE FRONT PANEL TO DISPLAY THE PARAMETERS ON FRONT PANEL MENUS ALLOWING THE MODIFICATION OF THE PARAMETERS MENUS ALLOWING THE MODIFICATION OF THE PARAMETERS MENU ALLOWING THE ADJUSTMENT OF THE PROCESS MENU ALLOWING THE ADJUSTMENT OF THE PROCESS MENUS ALLOWING THE EXECUTION OF ACTIONS TO USE THE DIGIPLEXER VIA THE ASCII PROTOCOL AND COM TO CONNECT A PC TO THE COM0 PORT CHOOSING A "TERMINAL" APPLICATION AND PRINCIPLES OF THE ASCII DIALOGUE THE ASCII INSTRUCTION SET RELATIVE TO THE HARDWARE CONFIGURATION OF THE FMX410 DIGIPLEXER 58 TO USE THE DIGIPLEXER WITH THE PC SOFTWARE SUPPLIED TO USE THE «DIGIPLEX» SOFTWARE TO CONFIGURE THE DIGIPLEXER HARDWARE DIGIPLEX SOFTWARE : GENERAL SET UP SCREEN (F2) DIGIPLEX SOFTWARE : GENERAL SET UP SCREEN (F2) PARAMETER CONFIGURATION SCREEN RELATED TO THE SIGNALS USED OR GENERATED BY THE DIGIPLEXER (F3) PARAMETER CONFIGURATION SCREEN RELATED TO THE SIGNALS USED OR GENERATED BY THE DIGIPLEXER (F3) LOGICIEL DIGIPLEX : GENERATING SIGNAL TEST LOGICIEL DIGIPLEX : GENERATING SIGNAL TEST DIGIPLEX SOFTWARE : DIGITAL MULTIPLEX SIGNAL DISPLAY TO CONFIGURE THE RDS PARAMETERS WITH THE "FMB10CFG" SOFTWARE (WINDOWS ) TO CONFIGURE THE RDS PARAMETERS WITH THE "FMB10CFG" SOFTWARE (WINDOWS ) TO USE RDS WITH THE FMX410 DIGIPLEXER A FEW WORDS ABOUT RDS ASCII INSTRUCTION SET FOR THE CONFIGURATION OF RDS DATA : FMX TO SET UP THE LIST OF AUTOMATIC FREQUENCIES TO BE TRANSMITTED TO SET UP THE PI AND PS CODES FOR THE FMX410 DIGIPLEXER Page 3 sur 87

4 TO CREATE A PS KNOWN AS "REVOLVING" OR "SCROLLING" (FMX410) TO SET UP THE DI, PTY, MS CODES OF THE FMX410 DIGIPLEXER TO SET UP THE TP CODE (FMX410) WHAT IS THE TA CODE USED FOR, HOW DOES IT WORK? SWITCHING THE TA. (FMX410) RADIO TEXT TRANSMISSION TO BROADCAST DYNAMIC DATA TO USE THE AUDEMAT-AZTEC "RDS-MCS" SOFTWARE TO ADDRESS THE RDS SECTION ASCII AND UECP (UER-SPB490) PROTOCOLS THE SWITCHING OF THE UECP (UER-SPB490) PROTOCOL LAYER 2 COMMUNICATION PROTOCOL AND TIMINGS REQUIREMENTS RDS CONTROL DIFFERENCES BETWEEN THE FMX410 DIGIPLEXER AND THE FMB10 ENCODER EXTENDED RDS : THE FMX440 DIGIPLEXER FREQUENTLY ASKED QUESTIONS (FAQ) WHAT IS THE RELATIONSHIP BETWEEN THE ACTUAL RDS LEVEL AND THAT DEFINED IN THE UECP (UER- SPB490) PROTOCOL? WHAT IS THE RELATIONSHIP BETWEEN THE ACTUAL RDS PHASE AND THAT DEFINED IN THE UECP (UER- SPB490) PROTOCOL WHY DOESN T THE LVLO LEVEL REACT ON THE BAR GRAPH DISPLAY? DOES THE DIGIPLEXER ALLOW DC COMPONENTS TO PASS? THE FIRST CHARACTER OF THE DISPLAYED PS FLUCTUATES ON CERTAIN CAR RADIO RECEIVERS Page 4 sur 87

5 Before starting... Have you read this manual? If the response to this question is NO, AUDEMAT-AZTEC invites you to spend a little time to read it. In addition to the information on the FMX410 Digiplexer product, you will find precious information concerning the principles of frequency modulation (FM) and of the RDS system in radiobroadcasting. We wish you good reading. If you have any comments concerning this documentation, please contact the AUDEMAT-AZTEC product manager. Page 5 sur 87

6 Introduction Why "DIGIPLEXER"?... Since 1990, AUDEMAT-AZTEC have worked in the RDS field. In doing so, we have been closely interested in the composite multiplexed signal which carries not only the RDS, but also the sound of the Radio Station that you are preparing to "DIGIPLEX ". Of course, from the beginning we have thought of proposing a Stereophonic encoder combined with an RDS encoder. This would have been simple, if we had, without technical innovation, integrated an analogue synthesis or "falsely digital" stereophonic encoder into our RDS encoder. Such a combination would have married 2 technologies and 2 performance levels without any relation. That s why AUDEMAT-AZTEC decided to create a new concept in FM : That is to synthesise globally and digitally the Multiplex signal : "Digiplex ", as in Digi(tal)-(Multi)plex. You have just acquired an FMX410 or FMX440 DIGIPLEXER... These products contain high technology developments incorporating the most sophisticated signal processing techniques. In practice, these are DSP (Digital Signal Processor) which by software, assure all the synthesis functions of the different composite multiplexed signal components delivered by the Digiplexer. Owing to it s technological progress in RDS (Radio Data System), AUDEMAT-AZTEC SA has invested technologically in the stereophonic encoding and multiplex processing (clipping, power enhancement, AGC of the FMX410 Digiplexer. The FMX410 Digiplexer ensures RDS and RBDS functions (For USA). Page 6 sur 87

7 DIGIPLEXER : 10 key points... 1 Price reduction of the functions due to their integration in a single unit. 2 Reduction in space taken in central control rooms and transmission sites 3 Flexibility of AUDIO, STEREO, RDS parameters and multiplex processing 4 Simplicity and repeatability of the digital configuration 5 Elimination of drift owing to a DSP based digital architecture 6 Extremely simple to operate owing to it s PC configuration software 7 A digital multiplex limiter which processes the multiplex signal at it s source 8 A product designed to accept the DDJ and NHK systems 9 A system and sampling frequency of adjoining signals of 500 khz 10 The complete remote control of parameters, via modem Page 7 sur 87

8 RDS data S T U D I O Audio (L, R) RS232/RS422 interface RDS data ASCII or EBU-SPB490 Protocol Audio Interface AES/EBU Analogue or Digital Digital RDS encoder Digital Stereo Encoder Digital Summation Σ Digital Multiplex Limiter Composite Multiplex Digital or Analogue F M P I L O T System sampling frequency Fech>400kHz. SYNCHRO DIGIPLEXER BLOCK DIAGRAM The block diagram above shows in a synthetic manner the operational blocks of the FMX410 Digiplexer. The Technology in the Digiplexer... 1 Digital audio input (AES/EBU S-PDIF) 2 Number of DSPs : 5, DSP operating frequency = approximately 60 MHz 3 Sampling frequency > 400 khz 4 Variable Gain Bypass function 5 Multiplex calculations and encoding performed in 24 bit, Fech > 400 khz 6 Digital adjustment of the analogue input level on a large dynamic range 7 Direct expression of the Multiplex signal level in khz. 8 Optional digital output of the Multiplex signal (requires 3 additional connectors) 9 A complete synchronisation unit for synchronous FM applications Page 8 sur 87

9 In the majority of cases, the Digiplexer ("Digital-Multiplex") replaces several pieces of equipment installed on the transmission site and/or in the studio. You probably find yourself partially or completely in the set up shown below (left), which describes in a general and schematic manner your actual transmission chain, and that which it will become, once the Digiplexer is installed: Audio (BF) Left, Right Before the AZTEC Digiplexer Digital or analogue audio signal coming from the studio by line, satellite or beam. After the AZTEC Digiplexer AES-EBU digital/ analogue converter A D DIGIPLEXER FMX410 Stereo Encoder Multiplex Limiter (Clipper+Optimiser) RDS Encoder A composite multiplexed signal is applied to the transmitter pilot. Frequency band 0 to 100 khz Pilot transmitter 87,6-107,9 MHz 10 to 50 Watts Transmission antenna Power amplifier 100W to 10kW Page 9 sur 87

10 FMX410 Digiplexer general specifications Audio inputs outputs: Digital audio input : XLR connector, galvanic insulation, symmetrical format. Auto-adaptation to the AES/EBU data formats applied. Compatible with the digital audio formats : AES/EBU, IEC958, S/PDIF, EIAJ CP-340 Adjustable level from 0dBfs to -10dBfs Emergency back-up : In case of synchronisation failure on the digital audio frames, automatic switching and capturing of sound signal on the analogue audio input. Analogue audio input : 1 connector XLR per channel Symmetrical format Impedance : 600 ohms (easily changed) Adjustable nominal level : -18dBu to +18dbu. Nominal reserve : 6dB Multiplex input : BNC, asymmetrical format. Adjustable nominal level : -18dBu to +18dBu. «Bypass and adder» function : configurable retransmission gain : -60dB to +20dB. Extraction of a Hz pilot signal contained in the MPX signal applied for the phasing of the Digiplexer clock. Digital Multiplex Output (option) : Sampling : Fech>400kHz, 16 bit serial bus CLK, SYNC and DATA compatible DSP. Applications: driving of DDS transmitters (Direct Digital synthesisers). Driving of Digital beams. Analogue multiplex output : BNC, Asymmetrical format. Nominal adjustable level : -18 dbu to +18 dbu. Recommended load impedance : 600 ohms. Nominal deviation : 75 khz Maximum deviation : 150 khz Stereophonic encoding : Harmonic distortion : < 0.03% (1kHz) Separation : Better than 60 db : (1kHz sinusoidal) 38kHz suppression : Better than 70 db. Audio pass band : Configurable by the DIGIPLEX.EXE software (delivered with the Digiplexer) between 20 Hz and Hz. Low pass filter for each audio channel : Better than -86 db attenuation at 16.7kHz, configured to 15kHz for a low pass filter (parameter configured at the delivery) Linear phase. High pass filter for each audio channel : Configurable from 0 to 15kHz with the DIGIPLEX set up software. Pass band ripple : Less than 0.1 db Pilot frequency deviation : Adjustable in khz, in steps of 0.1kHz (via front panel, RS232 or DIGIPLEX set up software) Driver frequency stability : 0.5Hz 0 C to 50 C Test signals : Predefined : Hz, Hz, 14843Hz sinusoidal. Channel combinations : Left only, Right only, Left = Right, Left = -(Right). Page 10 sur 87

11 RDS encoding: Out of band rejection : Conforms to the standard CENELEC EN50067 (Less than -96dB, CENELEC specified conditions). 57kHz suppression : better than 70dB Deviation : adjustable in khz (unit of deviation), steps of 0.1kHz RDS application examples on FMX410 : PS, PI, AF, RADIO TEXT, dgps, PTYN, FBT, RBDS. Compatibility with the FMB10 RDS encoder. Free format groups. Options : Upgrading the FMX410 into a FMX440 : RDS40 extension board : refer to the technical manual RDS40 (ref : RDS1930.DOC) Multiplex signal processing : Clipper : predicting Algorithm ( AUDEMAT- AZTEC property). Possibility to activate or desactivate from the front panel AGC : dynamic control of the analogue audio input with adjustment of ATTACK and DECAY time and GATE threshold Power enhancement : adjustable from 0 to 5 db (1dB step). Action on L-R : increasing or decreasing of the stereo effect Parametric display: Display : High luminosity LED alphanumeric display. Shows the digital values of the parameters related to stereophonic encoding, at input, intermediate and measured output levels. Bar-graph display of actual deviation 11 green LEDS, 1 yellow LED, 3 red LEDS, zoom mode, peak value of actual deviation. Configuration: Via COM0 (RS232): ASCII commands with a user friendly protocol can be used with a «terminal» type application. Via the «DIGIPLEX.EXE» PC software : Configuration software delivered with the product for Windows which permits the Stereo Encoding sections, limiter, and RDS data to be set up. The DIGIPLEX software integrates remote control via a Modem. Via the front panel : 2 buttons and an led alphanumeric display enable the configuration of the physical parameters of the Digiplexer. Saving the configurations : 2 memories containing the user defined parameters. 1 «factory configured» memory may be recalled for a rapid set up change. Saving of the configurations on diskette or hard disk via the DIGIPLEX.EXE set up program. Communication port(s): FMX410 : COM0 on front panel RS232 (1200 to 9600 bits/s). Protocols : ASCII. Configurable Modem initialisation sequence. UECP protocol (UER- SPB490) accepted for RDS and manufacturer commands. Page 11 sur 87

12 Monitoring: Display : peak digital value, 0.1kHz resolution. Bar-graph (LED display) : peak value, automatic zoom function in case of absence of modulation. DIGIPLEX configuration program : permit, in particular, the real time monitoring of the input signal and the Multiplex output signal. Power supply : Supply voltage : 115V/230V Voltage tolerance : +/-10% Supply frequency : Hz Supply filter : yes Parallel protection unit : Gemov Fuse : 250mAT (230V) / 500mAT (115V) Power consumption : 25VA Mechanical aspects : Height : 1U (44,5 mm) Length : 483 mm Depth : 220 mm Net weight : 7 kg Environmental data : Temperature (operating) : 0 C to 50 C ambient Temperature (storage) : -30 C to 80 C ambient Altitude : 0 to 5000 metres Humidity : Class F, DIN50040 Labo CEM : Télédiffusion de France CEM : EN50022 and generic standards. Hardened immunity : 10V/m minimum Page 12 sur 87

13 Physical components and interfaces The Digiplexer case Chassis : stainless steel. The chassis surface is conductive. Upper panel : May be dismantled for access to internal components Ventilation : Natural convection by upper and lower openings Rear panel (1) (2) (3) (4) (5) (6) (7) V Power supply (IEC) On/Off switch 115V/230V select IMPORTANT : The «EARTH» pin of the IEC connector is connected to the chassis of the Digiplexer. If the Digiplexer is not connected to earth, the potential difference of the chassis will float : it is not recommended to use the equipment in this manner. WARNING : The equipment ground is close to the chassis potential : Therefore, ensure that the equipment is connected to the earth via the IEC supply connector and not simply via the ground of one of the XLR, SUB-D or BNC connectors used. Page 13 sur 87

14 (1) RF Output (option) This output is only used for demonstration applications, factory use or for production lines of car radios, FM tuners and receivers of all kinds. The Digiplexer is then used as a test generator. For more information concerning this type of use, please contact AUDEMAT-AZTEC. (2) "AES/EBU" digital audio input Input for the AES/EBU signal. The signal to apply is symmetric, floating. A transformer assures the galvanic isolation of this input with reference to the Digiplexer voltage. The AES/EBU input is insensitive to the polarity of the applied signal. Pin AES-EBU digital input XLR female connector Signal 1 Digiplexer Ground. It is advisable to connect the screen of the cable used to this pin, if possible. 2 AES+. 3 AES- (3) Symmetrical analogue audio input (left channel) (4) Symmetrical analogue audio input (right channel) Pin Symmetrical Audio Inputs Female XLR connectors Signal 1 Digiplexer Ground. It is advisable to connect the screen of the cable used to this pin, if possible. 2 Audio (-). This pin is to connect pin 1 (gnd) for an asymmetrical audio supply 3 Audio (+) Page 14 sur 87

15 (5) Input/Output synchronisation signal Hz / FM-SYNC "MPX" Input / Output (asymmetrical) BNC connector Pin Signal Central Connector ground Synchronisation signal Digiplexer ground This input/output is frequently referred to as «SYNC port» in this document. (6) Composite input Signal - Multiplex (asymmetrical) Pin Central Connector ground "MPX" Input BNC connector Signal Composite Multiplex Signal applied to the Digiplexer Digiplexer ground (7) Composite output signal - Multiplex (asymmetrical) Pin Central Connector Chassis "MPX" Output BNC connector Signal Composite Multiplex Signal delivered by the Digiplexer Digiplexer ground Page 15 sur 87

16 Front panel AZTEC FMX410/440 DIGIPLEXER Aztec Logo 10 digit alpha display 2 push buttons to move around the different menus and modify the Digiplexer parameters. LED Bar graph deviation meter "COM0" port RS232 (female) FMX410 Pin "COM0" RS232 PORT (female) Signal 1 do not use 2 TX (DCE) 3 RX (DCE) 4 connected to pin 6 5 GND 6 connected to pin 4 7 connected to pin 8 8 connected to pin 7 9 do not use Page 16 sur 87

17 Internal composition of the Digiplexer The figure below shows the electrical and electronic components of the Digiplexer. Supply filter Digiplexer FMX410 DSP PCB Power supply PCB Toric transformer 10 digit alpha display PCB Page 17 sur 87

18 FMX410 PCB : jumpers, points of adjustment MICROC. Jumper J : bypass active when power on. 2-3 : no bypass when power on Jumper J : bypass active when power off. 2-3 : no bypass when power off. GAL Potentiometer P1 power on bypass Gain: fine adjustment (+/- 0,3dB) O P T I O N DSP DSP Jumper J23 Origin synchro DSP DSP DSP 1-2 : input BNC "MPX" 2-3 : input BNC "SYNC" Adjustable C189 Internal time base. LED SYNCHRO Not lit : Digiplexer synchronised on external source Lit : Digiplexer non synchronised on external source IMPORTANT The adjustment of the stereo separation can be performed with the P2 potentiometer. The procedure is described in the AUDEMAT-AZTEC AZT1851_0_2. doc document. The adjustment of this parameter has to be done in the best possible conditions (care to cables, quality, impedance). Page 18 sur 87

19 Schematic Digiplexer FMX410 J22 P1 Gain Relay J23 16bits Antialias. Relay MPX input J24 PLL D A Gain MPX output SYNC Input/ Output COM0 Display Level indicator Buttons C189 CPU RAM CODE E2PROM RS232 BUS EXT INT Digital Signal Processor Synthesis Multiplex STEREO + RDS Limiter Clipper Digital Multiplex Port 8-16Mbits/s Multiplex digitizing Option D A Analogue audio inputs (L&R) D A Digital audio (AES-EBU) DIG AES Interface ports with RDS40 PCB +5V +15V -15V Power supply system Page 19 sur 87

20 About the Composite Multiplex signal The Digiplexer is a global and digital synthesiser of the composite Multiplex signal used in frequency modulated radio broadcasting. This chapter presents a few technical components related to this signal. Multiplex signal composition Contrary to the audio signal that normally occupies a frequency band of 20Hz Hz, the multiplexing used in FM radio broadcasting today uses a frequency band of 0-100kHz. In fact, the transmission of the stereophonic signal and of the additional subcarriers such as RDS (RBDS for USA) is achieved by a frequency multiplexing of the different channels. The reasons for this multiplexing are historic, stereophonic encoding uses a principle perfected in the 1950s. If the principle of stereophonic encoding has not changed since this era, its application has followed the technological developments, as much in the level of multiplexing as in demultiplexing (stereophonic decoding). Stereo Pilot Amplitude L+R (mono) L-R S channel L-R RDS 5% Frequency 15 KHz 23 KHz 53 KHz 19 KHz 38 KHz 57 KHz 92 khz Note : 57kHz = 19 khz x 3 38kHz = 19 khz x 2 The stereophonic effect (L-R) is offset in frequency owing to the amplitude modulation of a 38kHz sinusoidal signal by this stereophonic component (L-R). The absence of the Hz carrier is explained by the fact that no dc component is present in the transmitted audio signal Page 20 sur 87

21 The 19kHz subcarrier, or pilot, carries a temporal and frequencial reference signal used by the stereophonic decoders, to demodulate the stereophonic effect (L-R). The RDS signal obeys to the same kind of frequency translation, applying a slightly more complicated AM technique, since it is seen as the combination of 2 modulating signals out of phase by 90. The extremely severe characteristics of synthesis prevent the RDS signal from overlapping the top of the stereophonic component. Other subcarriers sometimes profit from the FM spectrum, such as the SCA system (frequency modulation at 67kHz) popular in the USA and in a few stations in Spain. This unit transmits a sound signal (approx. 60hz - 8kHz pass band) for use in specific receivers (programmes for department stores,...). At last, multiple frequencies are used for the subcarriers : this precaution is essential to avoid the noise resulting from intermodulating products "falling" in the LF domain, which are often generated by medium quality FM receivers. Levels and units used to describe the Multiplex signal The levels and units used to express the magnitude of the Multiplex signal (frequency, amplitude) often lead to confusion. In fact, the confusion comes from the fact that the Multiplex signal frequency modulates the carrier (HF) situated in the FM band (87.6 to MHz) : the higher the Multiplex signal, the larger the deviation resulting from the HF carrier. The deviation of the HF carrier is expressed as a frequency unit as it is relative to the frequency of the HF carrier : for example, when one talks of a transmitter that transmits at 97.6 MHz 70 khz deviation, this signifies that the amplitude or the level of the Multiplex signal applied to the transmitter provokes a deviation of the HF carrier from MHz to MHz and at the rhythm of the modulation contained in the Multiplex signal. Thus, we can say that the pilot subcarrier whose frequency is 19 khz deviates or provokes a deviation (intrinsic) of 8 khz : in more technical terms, this means that the carrier frequency of the 97.6 MHz transmitter varies from to MHz at a rate of times per second. The international standardisation has maintained to specify a maximum instantaneous deviation of 75 khz of the HF carrier. This limit, fixed as reference, is frequently seen specified in % : 75 khz deviation = 100%. Page 21 sur 87

22 In USA one prefers to talk of injection levels which are normally expressed in % of 75 khz : 100% deviation corresponds to 75 khz deviation. IMPORTANT in the rest of this manual, the deviations or injection levels, which all represent the same thing are expressed in khz. The table below gives as an example the standardised deviations (in khz) for the STEREO or RDS as well as their equivalent in %. For the Digiplexer, these deviations translate in output «level». Typical deviation Max deviation Min deviation Multiplex Signal as a whole 75.0 KHz 100 % Pilot frequency 19 khz 6.8 Khz 9.0 % RDS signal 57kHz 4.0 KHz 5.3 % 8 KHz 10.6 % 1.25KHz 1.6% Table : standardised or specified deviations and % equivalents NOTE : AUDEMAT-AZTEC has organised the configuration of the Digiplexer Multiplex signal deviation level so that it appears as clear as possible : the unit of amplitude of the Multiplex signal is expressed directly in khz by the Digiplexer. The use of khz as unit is one of the wonderful advantages that the Digiplexer brings by it s global synthesis of the Multiplex signal : the MPX output level of the Digiplexer must be determined at the beginning, once and for all, as a function of the transmitter s characteristics. Page 22 sur 87

23 Principles of digital synthesis of the Multiplex composite signal The Digiplexer uses Digital Signal Processors (DSP) to perform the digital synthesis operations of the signal. The audio signal applied to the analogue inputs (or digital) is over-sampled by digital processing (dedicated DSP) of the Digiplexer system frequency (approx. 500 khz) : this extremely complex operation, which consists of obtaining a high sampling frequency, is essential for a high quality processing of a signal to be transmitted in FM. The audio signal is processed with the aid of digital filters, owing to operations called convolutions. The convolutions use parameter tables and the modification of the contents of these tables has an effect on the following parameters : - response curve - pass band (typically 20 Hz Hz) or other configurable limits - ripple in the pass band The AM operations (stereo L-R and RDS subcarriers) follow perfectly the mathematical equations which describe the types of modulation. No approximation is made in the setting up of the algorithms concerned, which operate on 24 bit at the system operating frequency (Fech close to 500 khz). The RDS signal is generated from the temporal equation of each RDS symbol, which spreads in time over several thousand Multiplex signal samples. The direct use of the mathematical equation, assures a faultless respect of the spectral characteristics imposed by the cosine filtering of the RDS signal (-86 db at 2.4 khz of the central RDS frequency which is 57 khz). All the (L+R), (L-R) signals modulated at 38 khz, 19kHz pilot frequency, RDS signals are then added respecting a weighting derived from the user configuration. The phase criterion between subcarriers (19 khz, 38 khz and 57 khz) is easily respected, since the signals come from the same system clock. The system clock, can be synchronised by an external source (19 khz) thus making it possible to synchronise several Digiplexer units between one another, and offer a synchronism of the multiplex signal for FM synchronous applications for example. Page 23 sur 87

24 Advantages of global digital synthesis of the Multiplex signal GLOBAL generation of the composite Multiplex signal... Elimination of cascading equipment each one carrying its own noise level Determination of the amplitude of the different components of the generated spectrum, with a single unit of deviation (khz). No more subcarrier synchronisation problems Multiplex synchronism assured owing to the synchronisation functions, ideal for synchronous FM applications. No more impedance and level adaptation problems between different equipment. Mutual protection of the various subcarriers and sub bands. In traditional architectures, the stereophonic decoders and Multiplex limiters often generated harmonics or undesirable components outside of the useful band. This is not the case of the Digiplexer. Improved reliability DIGITAL generation of the composite Multiplex signal... Elimination of the dispersion of the characteristics. No more level deviations between 2 tracks, or doubts about the subcarrier levels. Parametric flexibility. The different amplitudes (audio tracks and subcarriers) are independently adjustable, within realistic limits. Perfectly mastered filtering characteristics. Digital processing permits perfect prediction of the result to obtain. As such, the constant ripple of the audio input filter characteristics in the 0-15 khz band may be specified and/or modified, as well as the cut-off frequency which can easily be configured. Page 24 sur 87

25 Instantaneous deviation and power related to modulation The 75 khz deviation limit is imposed in a quasi global manner by various regulations as regards FM radio broadcasting. This is an instantaneous limit, i.e. this value of deviation may not be exceeded in any situation, or at any time. Certain radio stations are frequently measured as exceeding the 75 khz limit by 20% without necessarily, audibly, being aware of it. Inversely, one can often be surprised by the sound intensity of a radio station and have doubts on their respect of the standards. Why? The deviation, alone, is not the only revealing parameter of acoustic level (audible) that the listener can detect. In fact, if the deviation is an amplitude that describes a voltage or level, it does not completely describe the notion of "power" or "density" of the signal. The "power" of the composite or Multiplex signal is that which the listener notices. By associating the time factor with deviation, we arrive at the notion of deviation power. The deviation power is the object of today s studies intending to be regulated : this project does not have a technical origin like the 75 khz limitation but a desire to harmonise the audio signal power transmitted by stations to achieve a comfortable listening quality. Certain radio stations, whose opinion clearly opposes limiting the audio signal power, argue that freedom on sound power is a marvellous instrument of differentiation between radio stations : the sound of each station is different, and will remain different because it conveys subjective impressions, which a power harmonisation would mostly eliminate. The ability to strictly limit the deviation of the Multiplex signal to 75 khz, has a direct effect in raising it s power, as, because of the presence of a barrier, the audio input level (that which comes out of the mixing table or sound processing table) may be raised by 1 to 3 db without risk of breaking the 75 khz bar. The Digiplexer integrates this limiter function, which may be activated (11 preset adjustments) or deactivated. The "Multiplex Limiter " or " Multiplex Clipper " function The concept of a deviation limiter or «clipper» has been controversial, as the placing of a composite Multiplex signal limiter at the end of the audio and Multiplex chain have often the effect of destroying the spectral quality of the signal delivered and of the integrity of the 19 khz and RDS subcarriers. Page 25 sur 87

26 In fact, originally, a «clipper» was no more than a levelling function : the amplitude bumps passing a given threshold are simply "shaved". Naturally, the result is catastrophic for the spectrum, as much in the audio band as outside it where the pilot or RDS subcarriers were brutally amputated a fraction of their signal, according to the aléas of the audio signal! Since, substantial progress has been made by numerous French or American analogue equipment. The levelling notion still remains present, but it only applies on the audio band and, an efficient filtering (by rounding the ends) brings substantial improvements to the process. The process used by AUDEMAT-AZTEC, even if it seems similar to the composite signal clipper family and not to sound processing, has however an approach opposed to levelling. Owing to digital processing, the Digiplexer knows perfectly how to anticipate in a given time T what the Multiplex signal will be in T+ T : it can therefore act on the processed signal, during T ( T not possible to listen to, but long for digital processing = complex calculations and processing made possible). AGC function This function gives the possibility to dynamicaly adjust the sensitivity of the analogue audio input of the Digiplexer. It regulates the level differences at the audio inputs, especially when no sound processing equipment is connect before the Digiplexer. The Digiplexer allows the adjustment of the reaction timings of the AGC. The effects of the AGC function are rather slow compared to the other functions like the clipper, compressor or expender. "ADDPWR" function Based on the same principe of the Multiplex Clipper, it is possible, within the following limit (1 to 5 db) to digitally enhance the power of the Multiplex signal when the 75kHz limit is not reached, in order to optimise the excursion to this previous value. The function of enhancement of the Multiplex signal excursion has to be combined with the limiter, in order to keep the 75kHz limit in all cases. Page 26 sur 87

27 The MPX LIMITER POWER FUNCTION Description of the new commands Following commands have been included in the menu GOTOPROCESS of the 8 LED screen in the front side. They are also available in console or via HTML. MPX Power limiter Activation: LIMITER=0 NO power limiter LIMITER=1 Hard forced Power Limiter LIMITER=2 Smooth forced Power limiter LIMITER=3 Very smooth forced Power limiter Maximum MPX power level expected in db (0db by default): PWLVL=X.X 0<X.X<+6 db (by step of 0,1 db) MPX power limiter action can be controlled via the 8 LED screen in front side after the deviation and MPX power display: L: OFF Inactive Limiter G:+12 A:1 Active Limiter with Gain (NMPA or NMPN)= 12dB and ADDPWR to 1 db Activation of the MPX Power Limiter 1/ PROCESS=1: Process in active mode 2/ ADDPWR=x: Set the Add Power function at x db (0>= x >=6). This enables to manage an offset of Power augmentation of x db above the expected MPX power level, without any deviation lost. 3/ Adjust the input gain (NMPA or NMPN), in order to obtain an average MPX level according to the program type and the expected MPX power level. 4/ PWLVL=x: Set the MPX power threshold level at x db. (Above this value the limiter will act) 5/ LIMITER=1: limiter activation. Two-limiter regulation modes are available: First one is Hard forced Power mode = maximum variation up to 0.4 db/s (LIMITER=1) Second is Smooth forced Power mode = maximum variation up to 0.1 db/s (LIMITER=2) Note: It is strongly advice to do not activate the AGC with the MPX power limiter. Page 27 sur 87

28 Example of procedure for using the FMX410 limiter 1/ PROCESS=1: Activate the processing mode 2/ ADDPWR=2: Set the add power function at 2 db. It allows compensating for a 2 db above set point increase in power, without deviation loss. 3/ Set the input gain so as to obtain an average level compared with the program type and the set MPX power. 4/ PWLVL=3: Set the power at 3 db. 5/ LIMITER=1: Activate the limiter. Two limitation modes are available: LIMITER 1: Mode with strong constraint control the power with gain variation as high as 0.4 db par seconds. LIMITER 2: Mode with low constraint control the power with a maximum variation of 0.1 db par seconds. Note: We strongly recommend not activating the AGC when using the MPX limiter. Sub-carrier deviation The deviation of the sub-carriers obeys rules as simple as those for the sound signal for the simple reason that the average amplitude (or envelope) is not supposed to vary as a function of time Hz "pilot" sub-carrier This is the case of the non modulated "pilot" sub-carrier, that is simply a Hz sinusoidal signal. The amplitude of this sub-carrier is fixed by the standards, at 9% of the maximum deviation, thus approximately 6.8 khz. There is no point in raising this value. In fact, the actual stereo FM receivers use this signal to the maximum even when it is positioned at a considerably lower value. By default, the Digiplexer assures a deviation of the pilot sub-carrier of 6.8 khz. RDS sub-carrier signal This modulated signal presents a quasi constant envelope amplitude. The RDS sub-carrier deviation level must be between 1 khz and 8 khz for a reasonable operation. Contrary to the pilot sub-carrier, the deviation value of the RDS signal has a determining effect on the behaviour of RDS car radios. Page 28 sur 87

29 A considerable signal level (more than 4 khz) will have the effect of retaining a large number of car radios on the received frequency : in fact, these car radios take into account the quality of the RDS signal received to perform a frequency change. With the RDS sub-carrier set between 3 and 4 khz, the quality of the RDS signal is usually close to that of the audio signal and the frequency switching is done at the moment where the listening quality becomes subjectively precarious. With the RDS sub-carrier set to less than 2 khz, the car radio is prompted switch frequency when the signal starts to show some little defaults in quality. Such a setting is useful when the broadcasting network possesses a coverage where the transmitters considerably overlap one another The Digiplexer takes 4 khz as the default deviation value, for the RDS subcarrier. It is possible to set this deviation level above 10 khz. Effect of the sub-carrier deviation on the global deviation When the pilot and/or RDS sub-carrier are added, they modify the instantaneous deviation accordingly. Thus, a transmission without pilot sub-carrier, RDS and stereophonic effect would, in certain cases (intense stereo effect), apply more than double the instantaneous deviation to the mono track (L+R) than would the same stereophonic transmission with RDS. Deviation SIGNAL STEREO With RDS STEREO Without RDS MONO with RDS MONO without RDS RDS (khz) 4 4 Pilot signal (khz) 6,8 6,8 L+R (khz) 32,1 * 34,1 * L-R (khz) 32,1 * 34,1 * Global audio (L+R) and (L-R) 64,2 ** 68,2 ** TOTAL (khz) Page 29 sur 87

30 Table : Distribution of deviation between the different signals of a FM stereo transmission in RDS. * Indicates here a possible mean distribution but indicative arbitrary (example). When the limiter (clipper) of the Digiplexer is activated, the Digiplexer, with it s basic configuration (mono/stereo, with or without RDS) will achieve a limitation at 75 khz taking into account the levels attributed to each of the sub-carriers (stereo and RDS). The importance of sub-carrier synchronisation Synchronisation of the RDS sub-carrier with the pilot sub-carrier is necessary. If the RDS receivers never use the pilot sub-carrier (19 khz) to perform RDS decoding, a lack of phase relationship between the RDS sub-carrier (57 khz) and (19 khz) may generate pulsations of 0 to a few Hz, which can disrupt the RDS or stereophonic decoding. When the Digiplexer provides RDS and stereophonic encoding at the same time, the synchronisation between the 2 subcarriers is maintained implicitly and perfectly (without any variation or possible phase noise). In this mode, it is useful to set the phase at 90 rather than at 0 : this arrangement has the effect of reducing the combined 19 khz + RDS deviation by about 10% and to diminish the effects due to the phenomenon of audio intermodulation on old FM receivers. When the Digiplexer is used as a stereophonic encoder, it is useful to set the "SYNC" input/output to 19 khz "output" mode to supply the clock reference to an RDS encoder as master When the Digiplexer is used as an RDS encoder, it is necessary to set the "SYNC" input/output to 19 khz "input" mode (or in accordance with the case of the MPX input as reference input) to accept a pilot signal and to synchronise to it. Page 30 sur 87

31 Digiplexer Installation and User s Guide Power supply Check the value of the fuse at the back of the equipment (500mA) for 115V operation. Position the jumper corresponding to the supply voltage. The Digiplexer does not need to supplied via an UPS (Uninterruptible power supply) imperceptible to power drops, it meets the requirements and thresholds considerably more severe than those required in the European directive related to the electromagnetic compatibility of electronic equipment. WARNING Ensure that this equipment is directly connected to earth via the power cable and not indirectly via the chassis, one of the communication ports or the GND of one of the BNC connectors General installation layout of the equipment Physical location in a rack AUDEMAT-AZTEC has avoided the employment of forced ventilation for the Digiplexer, so as not to penalise the product with potential mechanical problems. Thus, take care not to cover the openings at the top and bottom of the product, which allow a natural circulation of air. Electromagnetic Compatibility The Digiplexer has been designed to be installed in FM transmission sites. Therefore, it meets requirements and thresholds considerably more severe than those required in the area of the European directive of electromagnetic compatibility of electronic equipment. Theoretically, no additional component is to be added to the product. A few precautions to take when wiring the product The equipment s RS232 ports are protected by means of 15V zener diodes mounted head to tail: this arrangement makes the ports more robust. However, AUDEMAT-AZTEC strongly advise against connecting on it s ports, wiring coming from a local exterior to that where the Digiplexer has been placed, ( possible large supply voltage differences, notably in the case of lightning strikes. Page 31 sur 87

32 Where to connect the incoming audio signal, Left, Right? Two types of inputs signals may be used, choose the input which corresponds to the format (digital or analogue) used : "analogue" audio input This input is presented in the form of two XLR connectors, one for the left track, the other for the right track. Refer to the «Rear panel» paragraph of the «Physical components and interfaces» chapter to know the pin-out of these connectors. Take care to respect scrupulously the points mentioned in this paragraph concerning the use of these inputs in symmetrical or asymmetrical mode. «Symmetrical» mode : The incoming audio signal presents itself generally in the form of two shielded cables, each one possessing 2 conductors, sometimes twisted. «Asymmetrical» mode : The incoming audio signal presents itself generally in the form of two shielded or coaxial cables, each one possessing only one central conductor. The Digiplexer do not cancel the DC input levels. The use of isolating transformers is required when the signal arrives on the transmission site via specialised lines : these isolating transformers generally equip the equalisation of the parameters of the specialised lines unit. The input impedance of the Digiplexer is 600 ohms, regardless of the mode used(symmetrical or asymmetrical). This purely resistive impedance is made up of a 600 ohm resistor connected directly between the positive and negative pins of each Digiplexer input. NOTE : If the audio source with which you wish to supply the Digiplexer presents an impedance considerably larger than 600 ohms, a consequent attenuation of the input level will be observed. In this case, AUDEMAT-AZTEC advise the use of a line amplifier in order to make the most of the Digiplexer s characteristics. For experienced technical departments, AUDEMAT-AZTEC can explain how to raise the impedance of the audio inputs by removing two electronic components (SMT resistors close to the analogue audio inputs). "Digital" audio input This input is presented in the form of an XLR connector. Refer to the paragraph «Rear panel» of the «Physical components and interfaces» chapter to obtain the pin-out of this connector. Page 32 sur 87

33 This port uses the AES/EBU format and supports a group of variants associated to this format. the Digiplexer automatically knows each format variant and how to adapt itself to use the maximum dynamic range of the audio signal (16 to 32 bit floating point). IMPORTANT : When the Digiplexer does not detect a valid signal at the terminals of its digital audio input, the analogue audio input is used for sound broadcasting. During digital audio use, the analogue audio inputs might be connected to an emergency analogue audio input or left disconnected. NOTE : The Digiplexer continuously analyses the digital audio input, and continues to do so even when broadcasting is done from the analogue inputs. If the "AES" parameter is set to 0 (AES=0), the Digiplexer will select the analogue inputs for broadcasting in every case. When AES=1, the Digiplexer automatically opts for the digital input, if a valid digital signal arrives on the AES_EBU input. Where to connect the MPX output of the Digiplexer The MPX output (composite Multiplex) is unique. It is asymmetric and must be connected to the input of the FM pilot transmitter. The MPX output is asymmetrical and the use of a 50 ohm coaxial cable or good quality shielded cable is advised to make this connection. This cable has to be as short as possible. The procedure for setting the MPX output level is part of a separate paragraph in this chapter. The Digiplexer may, of course, be connected on another type of equipment other than a pilot transmitter : - analogue or digital multiplex beam - RDS encoder Understanding and choosing the «Bypass» function The Digiplexer «Bypass» function is subtle and makes it possible to connect the product in the majority of transmission architectures. The BYPASS function is to be considered in the following two cases : Page 33 sur 87

34 Power off BYPASS: determined by the position of the J22 jumper, the power off «BYPASS» function when selected, passively relays any signal applied to the MPX input to the MPX output. This function makes the «Digiplexer» transparent to the composite Multiplex signal when it is switched off. Power on BYPASS : Determined by the position of the J23 jumper, the power on «BYPASS» function relays the signal applied to the MPX input to the MPX output. The relaying is done with a gain that can be configured by the command "GAIN=" and hardware refined with the potentiometer P1 located on the Digiplexer PCB, close to the rear panel. The following paragraphs give a non-exhaustive description of clever uses for the on and off BYPASS function. Installation of the Digiplexer with an external RDS encoder When an external RDS encoder is preferred to the one which is integrated in the Digiplexer, the configuration described in the figure below must be respected. IMPORTANT 1 : Check that the input level of the "MPX input" is set to "OFF", (GAIN=OFF) to avoid any noise that could result from this port configured as input when the input is floating. IMPORTANT 2 : Configure the SYNC port in 19 khz output mode (SYNC IO=O) and master mode (SYNC=INT), so that the Digiplexer, delivers a 19 khz synchronisation signal externally via this output. There are 2 possible ways to synchronise of the RDS encoder : synchronisation by extraction of the pilot clock derived from the MPX signal The «SYNC» port is not to be used in this configuration. Use this configuration if the RDS encoder does not have an external synchronisation input. synchronisation by separate 19 khz clock The «SYNC» port is connected to the «SYNCHRO» input of the RDS encoder. Digiplexer with SYNC external Port RDS encoder (mode "SYNCIO=O") MPX in with ("GAIN=OFF") MPX out 2 3 Audio External RDS encoder FM pilot transmitter Do not forget to make the following hardware and software configurations : Page 34 sur 87

35 - jumpers J22 et J24 in mode BYPASS non activated - jumper J23 : position immaterial - set : "SYNC_IO=O" - set : "SYNC=INT" (the Digiplexer generates the clock, master mode) Installation of the Digiplexer with an external Stereophonic encoder If an external stereophonic encoder is preferred to the one integrated in the Digiplexer, insert the Digiplexer in the transmission chain as follows : Digiplexer with external stereo encoder SYNC Port (mode "SYNCIO=O") MPX in ("GAIN=0, for example) MPX out 2 3 Audio External stereo encoder FM pilot transmitter Do not forget to make the following hardware and software configurations : - jumpers J22 et J24 in mode BYPASS activated - jumper J23 in position synchro by MPX input - set : "SYNC_IO=O" - set : "SYNC=EXT" (the Digiplexer receives the clock, slave mode) - set : "AUDIO=0" - set : "STEREO=0" Page 35 sur 87

36 Installation of the Digiplexer with an external composite limiter Digiplexer with external Multiplex limiter SYNC Port (mode "SYNCIO=O") MPX in MPX out 2 3 Audio External MPX limiter FM pilot transmitter - jumpers J22 and J24 in mode BYPASS non activated - jumper J23 : position immaterial - set : "SYNC_IO=O" - set : "SYNC=INT" (the Digiplexer provides the clock, master mode) Installation of the Digiplexer as an emergency backup to existing equipment In this mode, the Digiplexer is used as an emergency backup for equipment, intervening in the area of the Multiplex signal generation. Insert the Digiplexer just before the pilot transmitter. The Digiplexer BYPASS function will be continuously activated. If a problem is noticed, the Digiplexer may be powered up by means of an automatic unit or manually. Powering up the Digiplexer will provide the backup of the chain generating the composite Multiplex signal. Digiplexer maintaining the emergency backup of a Multiplex chain SYNC Port (mode "SYNCIO=O") MPX in MPX out 2 3 Multiplex Chain/line FM pilot transmitter Audio The Digiplexer is powered up only when it must provide the backup function! Page 36 sur 87

37 Do not forget to make the following hardware and software configurations : - jumper J22 in mode BYPASS activated (power off) - jumper J24 in mode BYPASS non activated (power on) - jumper J23 : position immaterial - set : "SYNC_IO=O" - set : "SYNC=INT" (the Digiplexer provides the clock, master mode) - To connect emergency backup equipment to the Digiplexer In the same mind as the previous paragraph, use the «BYPASS» function to allow an emergency Multiplex signal to go through the Digiplexer : simply interrupting the power to the Digiplexer will provoke the emergency action. To use the MPX input for the insertion of an SCA or additional signal The MPX input allows any type of signal to be injected into the Digiplexer. The signal applied to this input is affected a positive or negative gain (command GAIN=) ; the resulting signal is then added to the output MPX signal on the condition that the jumper J24 is placed in "bypass activated power on". This particularly interesting function allows the Digiplexer to accept any type of SCA, RDS, or other subcarrier signal. WARNING 1 : The Digiplexer does not process the signal applied to it s MPX input on the frequency plan: this signifies that you must be in control of the spectral quality of the signal, which one will be reflected at the output and counterbalanced with the gain fixed with the «GAIN=» command. WARNING 2 : In the same spirit, the deviation indication performed by the Digiplexer does not take into account the nature of the SCA (or other) signal applied to the MPX input! To synchronise the Digiplexer by an external clock (19 khz) The Digiplexer can operate in slave mode, i.e. it can synchronise the hardware and software clocks on an external clock: this function, allows the enslaving of a group of Digiplexers from a clock and offer a cheap synchronism of FM modulation. Page 37 sur 87

38 In the «standard» equipment configuration, this clock has a frequency of Hz to establish relations of synchronisation with the standard components intervening in the generation of the composite Multiplex signal. AUDEMAT-AZTEC can adapt the Digiplexer internal software for other clock frequencies on request. In the case where the Digiplexer receives an external synchronisation signal, set up "SYNC=EXT" (Digiplexer front panel or DIGIPLEX configuration software). The «synchronisation» can be intervene by the MPX input, or by the SYNC port: Synchro via MPX input : extraction of the 19 khz signal drowned in the multiplex signal applied to the "MPX IN" input. - configure J23 (origin synchro) in "MPX input" mode - set SYNC_IO=O (a 19 khz clock signal resulting from the synchronisation will be delivered by the SYNC port). Synchro via SYNC port : use of a 19 khz signal (of more than 100mVcc is advised, form advised: sinusoidal) for the synchronisation of the Digiplexer - configure J23 (origin synchro) in "input by SYNC port " mode - set SYNC_IO=I : the SYNC port is used as an input WARNING : ensure the quality of the signal serving to synchronise the Digiplexer is satisfactory. To do this, verify that the synchro LED (on the Digiplexer PCB) is not lit. (see representation of the PCB in the paragraph «internal composition of the Digiplexer»). To recover the Digiplexer clock reference (19kHz) The Digiplexer is able to provide a 19 khz signal +/-1 Hz, by it s «SYNC» port, synchronous with the transmitted pilot signal. To do this, make the following configurations : - Jumper J23 : in position "MPX input" - SYNC=INT : the Digiplexer provides synchronisation (Master mode) - SYNC_IO=O : SYNC port in «output» mode The delivered clock signal may be used to maintain FM synchronisation (synchronous FM). Page 38 sur 87

39 To adjust the nominal sensitivity of the Digiplexer audio inputs This operation consists of adapting the input characteristics of the Digiplexer to the audio signal level to be applied. When the Digiplexer uses the AES/EBU digital audio input, the adjustment of the level applied to the Digiplexer is done with the NMPN parameter. When the analogue inputs are used (or likely to be used in case of an emergency) the setting of the sensitivity of the analogue audio inputs is done with the NMPA parameter. These adjustments are done from the front face or via the PC terminal application or the "DIGIPLEX" configuration software. For simplification, the purpose of the procedure of adjusting the sensitivity of the audio inputs is to assign «the largest number of bits» of the audio signal that you are going to apply to the Digiplexer input. There are 2 ways to calibrate the analogue input level: «Theoretical» adjustment : This type of adjustment may be done if you know accurately, to the nearest db, the nominal level of the audio signal that you are going to apply to the Left and Right analogue inputs The nominal level is defined as being the level of the audio signal (400 Hz frequency) which will produce a maximum FM deviation (75 khz) in mono. This level must be expressed in db and represents the NPMA parameter : Example 1 : The nominal level applied to the Digiplexer is +12dBu, configure NMPA=-12dB (standard value configured at the delivery). Example 2 : The nominal level applied to the Digiplexer is -6dBu, configure NMPA=-6dB. "Empirical" adjustment (most sure): Inject an audio level which is considered as being representative of the maximum allowable level into the Digiplexer. Adjust the LVLI parameter until - all the green LEDS of the bar graph display are lit - the yellow led is at the limit of turning on, but not lit (corresponds to 75kHz) - red LEDS never lit (not more than the nominal deviation) - if the level shown is too high raise NMPA - if the level shown is too low diminish NMPA Page 39 sur 87

40 in order to calibrate the digital input level : the NMPN parameter is in dbfs (full scale) taken into account that 'full scale) is the maximum value that can have a digital audio sample. The most usual value is NMPN=-4dBfs (factory adjustment) Please operate in the same way for the adjustment of the analogue inputs (2 methods) with the NMPA parameter. NOTE : these adjustments may be done without the Digiplexer connected to the pilot transmitter. To adjust the nominal output level (LVLO) of the Digiplexer The purpose of adjusting the output level of the Digiplexer is to adapt the Digiplexer output characteristics to that of the equipment which the Multiplex signal will be applied to: this is generally an FM pilot transmitter or a hertzian beam feeder. WARNING : to perform these adjustments, it is imperative to deactivate all signal processing functions (PROCESS=0). «Theoretical» adjustment : Assign to the LVLO parameter (output LEVEL) the value of signal level (400 Hz sine wave) which provokes an FM deviation of 75 khz (mono without RDS and any other subcarrier) on the pilot transmitter The Digiplexer takes into account the pilot RDS and additional programmed subcarriers. Negative and positive values are allowed for the «LVLO» parameter. "Empirical" adjustment : IMPORTANT : before making this adjustment, it is imperative to switch beforehand into the desired FM transmission mode: 1 configure the presence or absence of stereo (STEREO=1 or STEREO=0) 2 adjust the pilot sub-carrier deviation to the desired value (LVL19=) 3 configure the presence or absence of RDS transmission (RDS=1 or RDS=0) 4 adjust the RDS sub-carrier deviation to the desired value (LVL57=) Page 40 sur 87

41 5 start the mode TEST1:L,R 6 Then adjust "LVL0" to reach the 75 khz value indicated by a test receiver (e.g. RDS Monitor or FM Navigator type). It is equally possible to use a spectrum analyser or indication supplied by the bar graph or the vu-meter of the pilot used (on the condition that one is certain of this measurement). IMPORTANT NOTE : the value LVLO has no incidence on the display of the deviation value, or on the bar graph of the Digiplexer. The deviation values indicated by the Digiplexer are not measurements and the precision of this indication depends on the adjustment of the LVLO parameter. In certain cases, it could be necessary to tune the input level adjustment of the pilot transmitter, when it is possible, to achieve an optimal setting (to the nearest 0.1dB). Reminders on the pre-emphasis function The pre-emphasis function consists of increasing the high audio frequency levels in relation to the low audio frequencies. The purpose of this is to reduce the signal to noise ratio by a proportion of 10 to 15dB by performing the inverse operation at the reception level. The Digiplexer achieves the pre-emphasis operations in a purely digital manner, regardless of whether the transmission mode is mono or stereo. Depending on the installation s location in the world, set P_EMPH=50 (µs) (EUROPE) or P_EMPH=75 (µs) (USA). If the pre-emphasis function is achieved by external equipment, set P_EMPH=OFF to inhibit the preemphasis function of the Digiplexer. Monophonic transmission Monophonic transmission consists of transmitting only the Mono track (Left + Right) and the RDS signal. To do this, set the «STEREO» parameter to 0 (STEREO=0). The Digiplexer will then digitally suppress the following two signals : - stereophonic effect (38kHz signal) suppressed. - pilot frequency (19kHz) suppressed. Page 41 sur 87

42 The suppression of the pilot frequency permits the audio level to take a slightly more important part of the deviation than in the case of a stereophonic transmission. The Multiplex limiter will, of course, take this aspect into account. IMPORTANT NOTE : In the case of a monophonic transmission, it is imperative to supply the 2 Digiplexer inputs, either with a mono programme, or a stereo programme : the Digiplexer always does the L+R operation. If the Digiplexer is only supplied in mono by one of the audio inputs, 6dB must be subtracted from the setting value NMPA in order to compensate for the lack of signal on the other input. Stereophonic transmission The stereophonic transmission consists of transmitting the two following signals in addition to the mono signal : - stereophonic effect (38kHz signal). - 19kHz pilot frequency. Configure STEREO=1 to place the Digiplexer in this operational mode. To transmit the test signals Several types of test signal may be transmitted by the Digiplexer at various possible frequencies. In particular, they allow the calibration of the broadcasting channels. The table below shows the different test signals that are obtainable with the Digiplexer These test signals can be activated via the front panel, the ASCII protocol or the «DIGIPLEX» configuration software. NOTE 1 : The transmission mode of the test signal is limited at 2 minutes. It must be reactivated. Page 42 sur 87

43 Test signal: TESTn:xxxx xxxx L,R L,-R L,0 0,R n 0 No test signal No test signal No test signal No test signal 1 593,75Hz Left = Right (mono) 593,75Hz Left = Right (L-R track) 593,75Hz Left = 0 593,75Hz Right= ,5Hz Left = Right (mono) 1187,5Hz Left = -Right (L-R track) 1187,5Hz Left = ,5Hz Right= Hz Left = Right (mono) 14843Hz Left = -Right (L-R track) 14843Hz Left = Hz Right = 0 NOTE 2 : The test signals are always sinusoidal. The settings of the input sensitivity do not affect the test signal. The deviation produced by the test signals is always 75 khz. NOTE 3 : The test signals are transmitted respecting the configuration of the Digiplexer and the level transmitted in this mode is automatically defined in such a way so that : 75,0kHz = {Audio level L+R} + {LVL19} + {LVL57} The 593,75 Hz "L+R" test signal (TEST1=L,R) allows the Digiplexer output level to be calibrated : in this mode the nominal output level «LVLO» of the Digiplexer can be adjusted so as to generate a deviation of the carrier equal to 75 khz on the pilot transmitter or the broadcast channel used. See the setting procedure in the paragraph «To set the nominal output level of the Digiplexer» in the chapter «Installation and user s guide»... Page 43 sur 87

44 Multiplex processor operation (AGC, CLIP, ADDPWR, SEFFECT) 4 functions dedicated to Multiplex signal processing are implemented in the Digiplexer : AGC This function gives the possibility to dynamically adjust the sensitivity of the ANALOGUE audio input within a range of +6 to 6dB, depending on the analyse of the audio signal connected at the audio input. This function can be set with the following parameters : GATE threshold of the audio input level (below this threshold, the AGC function is frozen) ATTACK : attack time at the audio input DECAY : decay time at the audio input These parameters can be set either from the front panel (buttons and display) or with the DIGIPLEX software or with ACSCII protocol commands. CLIP The Multiplex Clipper implemented in the Digiplexer is one of the most complicated function of the equipment. Thanks to the AUDEMAT-AZTEC algorithms, the Digiplexer knows how to limit the audio (L+R) and (L-R) multiplex signal in order to keep the 75kHz limit without any effect on the quality of the audio signal (as long as the audio input level stays reasonable) ADDPWR With a predictive algorithm, this function enhance the Multiplex power from 1 to 5 db. This function has to be associated with the CLIP function in order to keep the 75kHz excursion limit. SEFFECT SEFFECT acts on the L-R part of the Multiplex signal and gives the possibility to reduce (SEFFECT=- 1 to 9) or to increase (SEFFECT=1 to 9) the stereo effect. Note : these 4 functions can be activated or not activated with the PROCESS parameter of the 'Gotoprocess' of the front panel or with an ASCII command. Then, for activating at least one of these functions, the condition PROCESS=1 is necessary. Page 44 sur 87

45 To modify the cut off frequencies on the audio tracks (L+R) et (L-R) This function permits the individual adjustment of the high and low cut-off frequencies for each audio band (L+R) and (L-R). To do this, it is imperative to use the «DIGIPLEX» configuration software. Reduction of the pass band of the audio signal : It is possible to reduce the high cut-off frequency of the signals L+R and/or L-R to eliminate unwanted noise. Certain data transmission components buried in the audio signal use the audio frequencies in the upper part of the pass band (ex : 14.9 khz). The Digiplexer can be configured to suppress this frequency by placing for example the high cut-off frequency at 14.5 khz. To save the current configuration in user memory This function (SAVE>USER1 or SAVE>USER2) permits 2 different configurations, typical of the Digiplexer, to be put into permanent memory and recall them at need. These configurations include the following points : - all RDS parameters (except for the FMX440) - all Digiplexer parameters To use the configuration in user memory for transmission The functions «REST<USER1», «REST<USER2», «REST<FACTY» permit the Digiplexer to be configured with the previously memorised parameters in the user memories. The "factory configuration" may be recalled, by activating the function "REST<FACTY". Page 45 sur 87

46 To restrict access to the Digiplexer parameters Access protection is achieved via the parameter «NKEY» which represents a secret code between 1 and 255. When NKEY=0, access is not restricted. When access is restricted (NKEY<>0) : - it is possible to visualise the parameters configured (via PC terminal or the front panel) - it is not possible to modify the set up parameters To access the parameters, the value of the «KEY» parameter must be modified to the value of the secret code. The KEY parameter sets the value to "0" three minutes after the last action performed on the front panel or the communication port. If you forget the secret code, contact your nearest Distributor indicating the serial number of your equipment : he will give you an unlocking code under certain conditions. To personalise the welcome message of the Digiplexer (front panel) If you do not use the welcome message to initialise a modem, it may be programmed to display the (scrolling) message of your choice during power up of the equipment. See the protocol command ASCII «WELCOME_TEXT=» To use the Digiplexer with a Modem By connecting a simple, commercially available modem to the FMX410 Digiplexer, it can be accessed at any moment : all the Digiplexer parameters can be configured remotely and the input and output level variations can even be observed. You can connect a Modem to the COM0 port of the FMX410 Digiplexer. During power up of the FMX410 Digiplexer, it can send a series of entirely configurable initialisation lines to this modem. 250 characters may be used for this purpose. The ^M sequence of characters demands the Digiplexer to send a Carriage Return between 2 MODEM initialisation commands. For any details, see the ASCII "WELCOME TEXT=" protocol command. Page 46 sur 87

47 Example: You would like the Digiplexer to call the number « » each time it is powered up : Enter the following command : "WELCOME_TEXT=ATDT, ^M" Refer to the notice of your Modem to know the initialisation string required (HAYES commands). For all the practical details, see the protocol command ASCII "WELCOME_TEXT=" The parameters are : - automatic pick-up mode(hayes standard command ATS0=0) - serial port speed, modem Digiplexer link : fixed to 9600 bauds, see the SPEED command - connection mode and speed Connection cable DIGIPLEXER - MODEM : SubD 9 male Digiplexer SubD 9 male Modem connect pin 4 to 6 connect pin 7 to 8 DIGIPLEXER - MODEM connection cabling details SudD 25 male Modem connect pin 4 to 5 connect pin 6 to 20 To display the composite multiplex output level VALUE INDICATOR : The output level is given in the menu " _vvv.vkhz" in khz: this only reflects in a relative manner the level delivered by the Digiplexer to the FM pilot. This is why, it is necessary to play with the LVLO parameter to precisely adapt the Digiplexer to the equipment (pilot or beam feeder) to which it delivers the composite Multiplex signal. The LVLO value is expressed in dbu and corresponds to the output voltage level when the display indicates " 75.0kHz". Page 47 sur 87

48 DEVIATION INDICATOR (BAR-GRAPH) The table below shows the behaviour of the bar graph, this is only the image of the menu " _vvv.vkhz" BAR GRAPH : MULTIPLEX Display Multiplex output " xxx.xkhz" Display Multiplex output " xxx.xkhz" LED the signal passes... the signal passes... red lit = expanded scale not lit = normal scale green n 1 1 khz 10 khz green n 2 2 khz 20 khz green n 3 3 khz 30 khz green n 4 4 khz 35 khz green n 5 5 khz 40 khz green n 6 6 khz 45 khz green n 7 7 khz 50 khz green n 8 8 khz 55 khz green n 9 9 khz 60 khz green n khz 65 khz green n khz 70 khz yellow 12 khz 75 khz red n 1 13 khz 80 khz red n 2 14 khz 90 khz red n 3 15 khz 100 khz khz R1 V1 V2 V3 V4 V5 V6 V7 V8 V9 V10 V11 J R1 R2 R khz The switching between the normal scale and the expanded scale is done automatically : the first red LED "flashes" when the display is showing the extended scale, which allows the observation of the subcarrier levels. To display the predicted deviation (Multiplex signal) on PC Use the "DIGIPLEX.EXE" configuration software : the evolution of the instantaneous multiplex signal and Multiplex processing action (AGC, CLIP, ADDPWR) can be observed in graphic form. The indicated levels are "unquestionable" and are not the result of the measurement: they are the "peak" result of mathematical operations performed by the Digiplexer times per second. Page 48 sur 87

49 The displayed deviation is only "estimated" in the way that it s accuracy depends on the setting of the "LVLO" parameter and the characteristics (linearity and modulation) of the equipment driven by the Digiplexer. To display the predicted power (Multiplex signal) on PC VALUE INDICATION : the power of the Multiplex signal is given in db in the menu "PWRavv.vdB". This value is continuously calculated with the digital sample of the Multiplex signal of the last minute. The calculation is done on a scrolling window of 1 minute. The Multiplex power can also be displayed with the DIGIPLEX software on a PC. NOTE : the power displayed is only a "prediction", in fact the accuracy of the value depends of the right adjustment of the parameter "LVLO" and the features (modulation linearity) of the equipment controlled by the Digiplexer. To display the action of the AGC function VALUE INDICATION : The gain or the attenuation generated by the AGC function on the analogue audio input is displayed in the menu "AGC :av.v x". a=+ or -, X=G if the audio signal is below the GATE threshold, then the function is frozen. v.v shows the gain (applied at the analogue audio input) if a=+ or the attenuation if a=- The action of the AGC function can also be displayed on a PC screen with DIGIPLEX software. NOTE : the menu is displayed only if the function is active : AGC=1 and PROCESS=1. Page 49 sur 87

50 Automatical procedure for the analogue inputs calibration With automatical "CALIBRATE" procedure the DIGIPLEXER calibrates its analogue inputs. This procedure cancels any DC signal that would come from the existing analogue components. The noise level at the analogue inputs is also analysed and an error message is displayed on the display (exempla : "ERROR L NOIS" ) if an anormal level is detected : in this case contact your distributor. IMPORTANT before launching the "CALIBRATE" procedure it is imperative to disconnect the analogue inputs of the DIGIPLEXER. The "CALIBRATE" procedure can be initialised in 2 ways : with the front panel key buttons, in the ACTIONS menu with the ASCII command : <CALIBRATE> NOTE : this procedure is performed for each value among the 74 value of the NMPA (displayed on the display), it takes approximately 5 minutes. Page 50 sur 87

51 To use the Front Panel To use the display and the "SEL" and "OK" buttons The display, the buttons and the bar graph on the front panel enable Digiplexer hardware to be configured simply and quickly. Those who know how the AUDEMAT-AZTEC AZ1 RDS monitor operates, will find one of the characteristics that made the product successful on the front panel of the Digiplexer. The two buttons must be manipulated independently. There are no subtle actions that require the 2 buttons to be pressed simultaneously. The «SEL» button serves to move around a group of menus. The «ENTER» button serves to modify the value of a displayed parameter, or perform the action proposed by the display. There are three groups of menus : values and status display menu group parameter display and modification menu group action performing menu group Concerning the parameters, the first touch on the «ENTER» button makes the "=" sign flash between the parameter and it s value : whilst the "=" sign is flashing, it is possible to modify the value of the parameter by playing with each button «SEL» and «ENTER» which decrements and increments the displayed value or index respectively. Before passing to another parameter, wait approximately 2 seconds for the "=" sign to stop flashing : the parameter has now been entered into memory. NOTE 1 : when you use the configuration program supplied with the Digiplexer, AUDEMAT-AZTEC recommend setting NKEY=0 during the use of the configuration software. NOTE 2 : For simplification, the syntax used to display the parameters, their modification and the performing of actions is compatible with those used by the ASCII protocol. NOTE 3 : Display brightness : use the menu command DISPLAY = to adjust the brightness of the 10 digit display. VERY IMPORTANT : The RDS parameters other than those influencing the RDS subcarrier (layer 1) are not accessible from the front panel. FMX410 : use the configuration utility for Windows, supplied with the Digiplexer, to set up the RDS logic parameters ; the ASCII protocol can also be used. FMX440 : see the manual (ref RDS19301). Page 51 sur 87

52 Welcome Messages on the front panel Power up or Digiplexer RESET AZTEC......WELCOME DIGIPLEXER TYPE 410 Welcome message that appears on power up of the equipment or after a RESET. In all cases : TYPE of Digiplexer Version (VER:) RDS1545x To Display the parameters on front panel _vvv.vkhz Predicted peak multiplex deviation level in khz. See LED indicators at the end of precedent chapter PWRaxx.xdB: Multiplex Power in db The calculation is done over a scrolling window of 1 minute. INP:xxxxxx Displays which audio source, "DIG" (digital) or "ANA" (analogue), the Digiplexer uses for broadcasting the sound signal. Displaying this function is useful when AES_EBU=1. SEL button ** * AGC:ax.x_G COM0:xxxxx This indication is displayed only if the analogue audio input is active and if PROCESS=ON and AGC=1. Ax.x indicates in db the gain generated by the AGC function compared to the input level fixed with the NMPA parameter. 'G' appears at left when the audio level is below the GATE level For the Digiplexer FMX410 only, xxxxx=ebu to indicate that the active protocol on COM0 is the UER(EBU) SPB490 protocol, xxxxx=ascii when the protocol is ASCII. When EBU=1, depressing the Enter key forces the Digiplexer to switch from one protocol to another. * RDS_TA:b Shows the state of the dynamic RDS parameter "TA", displayed in real time. GotoParams GotoAction PARAMETERS: See following pages ACTIONS: See following pages * not displayed for the FMX440 version ** this menu is present only if the analogue audio input is active and if PROCESS=1 and AGC=1 Page 52 sur 87

53 Menus allowing the modification of the parameters * KEY=nnn AUDIO=n STEREO=b ENTER key The ENTER key modifies the value of the displayed parameter. During the modification, the "=" sign flashes rapidly. Depress the "SEL" key to record your choice. entering the secret code which allows the modification of parameters or to perform actions. This menu is present if a code has been programmed by NKEY=. Suppresses the audio signal (L+R) and (L-R). Useful when using the Digiplexer as a RDS or TSE SWIFT encoder without an audio output. Mono Mode (b=0) / Stereo (b=1) SEL Key LVL19=kk.k RDS=b LVL57=kk.k DATA=b HSS=b LVL76=kk.k Deviation of the pilot subcarrier expressed in khz. kk.k from 0.0 to 15.0 khz Activates (b=1) or deactivates (b=0) the RDS subcarrier Deviation of the RDS subcarrier expressed in khz. kk.k from 0.0 to 15.0 khz Inhibits (b=1) the transmission of RDS data whilst maintaining the subcarrier active. DATA passes automatically to 0 after 1 minute. This parameter cannot be used. This parameter cannot be used. * * LVLO=sdd.d NMPA=sdd.d NMPN=sdd.d GAIN=ddd.d AES_EBU=b_ PROCESS=n_ P_EMPH=xx_ SYNC_IO=x_ SYNC=xxx BYPASS=b TESTn=xxxx SPEED=nnnn ECHO=b Sets the nominal output level : sdd.d between and 18.0 dbu for an excursion of 75kHz. sdd.d 'OFF' <=> inhibition. Sets the nominal NMPA of the analogue audio inputs : sdd.d between and dbu or 'OFF'. see <=> "To set the sensitivity of the audio inputs" Sets the sensitivity of the digital audio input: ddd.d between and 0 dbfs or 'OFF'. More details: rf to paragraph "To set the sensitivity of the audio inputs" Sets the bypass gain of the MPX input to the MPX output : sdd.d including between and (db) or 'OFF'. b=0 forces the analogue inputs to be used as audio sources. with b=1, the Digiplexer opts in preference for the digital input. n=0 No Multiplex Limiter, n=1 limiter only, n=2-6 CLIPPER +1 to +5dB; n=7-11 CLIPPER +1 to +4dB with reduction L-R Selects the type of pre-emphasis : xx=off for no pre-emphasis, xx=50 (µs) for Europe, xx=75 (µs) for the USA. Defines the sense of the SYNC port x=i for "input synchronisation", x=o for "output synchronisation" Defines if the Digiplexer provides the 19kHz clock in master mode (SYNC=INT) or if it must receive the external 19kHz clock (SYNC=EXT) Activates the BYPASS relay function (b=1) = identical effect to the Digiplexer POWERED DOWN. Normal operation : (b=0). TEST modes. For more details see the paragraph devoted to this mode: Chapter Installation and user s guide...", pgph. "To transmit the test signals". Sets of the speed of the COM0 port: nnnn=1200, nnnn=2400 nnnn=4800 or nnnn=9600. Never any parity, always 1 stop bit. (FMX410 only). Activates (b=1) or deactivates (b=0) the ECHO on the communication port COM0. (FMX410 only). * not displayed for the FMX440 version Page 53 sur 87

54 Menu allowing the adjustment of the PROCESS * ** ** ** * * CLIP=nnkHz ADDPWR=ndB SEFFECT=ax Activates (n=1), desctivates (n=0) the functions of the menu PROCESS : AGC, CLIPPER, ADDPWR, SEFFECT. If n=0 it inhibits the access to these parameters n=1 activates the AGC function. The respective @GATE are accessible. If n=0, AGC is inhibited, the adjustments are hidden. x=+ or x=-, nn is in dbu. xnn indicates the threshold. Below this threshold the AGC function is frozen. nn=1 to 99. Reaction time to an increasing of the audio input level. nn=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 corresponds to 20s/dB nn=1 to 99. Reaction time to an increasing of the audio input level. nn=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 corresponds to 20s/dB nn=60 à 99 or OFF. Max value of the excursion. The Clipper will cancel all modulation peak which would generate an overtaking of this limit. n=0 à 5. Increase of the Multiplex power of ndb. Note : ADDPWR is optimised for an operation with CLIP=75 a=+ or -; x=0 à 9. Si a=+, SEFFECT increase the stereo effect. If a=-, SEFFECT decrease the L-R part of the MPX signal from 10% if x=1 to 90% if x=9. * Ces menu are displayed only if PROCESS=1 ** Ces menu are displayed only if PROCESS=1 et AGC=1 Menus allowing the execution of actions SAVE>USER1 SAVE>USER2 REST<USER1 REST<USER2 REST<FACTY CALIBRATES Stores the current configuration (broadcast) in the memory USER1 Stock the current configuration in the memory USER2 Assigns the whole of the parameters stored in the memory USER1to the current configuration (broadcast) Assigns the whole of the parameters stored in the memory USER2 to the current configuration (broadcast). Assigns the whole of the factory parameters. to the current configuration (broadcast) Launch the calibration procedure for the audio analogue inputs. For this procedure, it is imperative to disconnect the analogue audio inputs. DISPLAY=n Display brightness, minimum for n=1, maximum for n=5 RESET Trigger hardware Reset of the Digiplexer Page 54 sur 87

55 To use the Digiplexer via the ASCII protocol and COM0 To connect a PC to the COM0 port To connect of a PC to the Digiplexer for configuration purposes, use the SUB-D9 connector located on the front panel and labelled "COM0". Look for the communication port not used by your computer. If the available port is presented in the form of a DB25 connector, use a standard SUB-D9 (male) to SUB-D25 (female) adapter. Do not use the port used by the mouse. Connect the available communication port of your computer to the port of the Digiplexer with a ribbon cable (non crossed), preferably the one supplied with the equipment. Choosing a "terminal" application and principles of the ASCII dialogue To communicate as directly as possible with the Digiplexer, AUDEMAT-AZTEC recommend the use of an ASCII terminal operating in MS-DOS or Windows. The DIGIPLEX configuration software also integrates a "terminal" application which is simple to set up and use. Terminal proposed for Windows 3.x, Hyperterminal for Windows 95 present all the characteristics to easily communicate in ASCII mode with the Digiplexer. If you require a higher level terminal, refer to the following chapter, which describes in detail, the installation of the AUDEMAT-AZTEC configuration software for a very user-friendly configuration. Windows 3.X In the Windows programme manager, open the "accessories" group installed automatically with Windows. In this group, you will find the "Terminal" application, normally represented by an icon containing a yellow telephone with a modem underneath interposed on a blue PC monitor. Open the application. In the "Parameters" menu, select "Communications" and adjust the parameters as follows : Transmission speed : 9600 on standard, otherwise, programme the same speed is for the PC and the Digiplexer (SPEED=) with the help of the display and buttons. Data bits : 8 Stop bits : 2 Parity bit: None Flow control : None Page 55 sur 87

56 Port : the available port you have used on the PC Parity control : don not tick the check box Carrier detection : do not tick the check box Windows 95 In the START menu, choose Program, then Accessories and open the file Hyper Terminal. Launch the Hypertrm application et give a name, DIGIPLEXER for example. Then select in «Connect» : «Direct to Com x» with x as the free communication port of your PC. In the 'COMx property' window that appears, select : Bits per second : 9600 standard, otherwise care that you have the same speed programmed for the PC and the DIGIPLEXER (SPEED=) Data Bits : 8 Parity : none Stop Bits : 2 Flux Control : None Once the terminal has been configured, it is ready for use. To check if the hardware and logic configurations function as planned, type "?" then <Enter> to display the Digiplexer general set up. If nothing is displayed on the screen, try a second time, otherwise, check the following points : Is the Digiplexer switched on? Cable Transmission speed of the Digiplexer (see menu "SPEED=" on the Digiplexer 410 display) Re check the configuration of the terminal application For displaying on the screen the commands entered via the keyboard type the command "ECHO=1" Before moving on to examine the numerous commands that are available, the structure of the Digiplexer command interpreter is explain below : The Digiplexer command interpreter meets the following rules. Any instruction sent to the Digiplexer must be validated by <Enter>. Command without parameter (action) Ex: RESET <Enter> Command with parameter Ex: TEST1=0,R <name of the action> < name of the action> = <value> Assign a value to a parameter Ex: STEREO=1 <name of the parameter> = <value> Page 56 sur 87

57 If a command entered leads to a process with success, the "+" character followed by one or several line return characters is sent by the Digiplexer. If a failure occurs (command not understood or incorrect parameter) the "!" character is sent under similar conditions. The ASCII protocol command syntax is compatible with the syntax used for the display of parameters, their modification and performing of actions by the front panel. IMPORTANT: the processing of the protocol commands by the FMX410 Digiplexer and the modification of the parameters by the front panel may be protected by a secret code (number entered between 0 and 255, see protocol commands KEY=, KEY? and NKEY=). When access to the Digiplexer is protected by a secret code, an error message is sent to any attempt to modify a parameter. IMPORTANT : the following paragraph and the following chapter describe the ASCII instruction set of the FMX410 Digiplexer (hardware and RDS parameters) This set has been separated into two parts: Instruction set to modify the hardware : compatible, with a few exceptions, with the menus proposed on the display of the front panel). Instruction set modifying the RDS parameters. These instructions are only possible via the ASCII protocol and only concern the FMX410 version. (See chapter «To use RDS with the Digiplexer"). WARNING : The FMX410 Digiplexer also supports the UECP (UER-SPB490) via COM0, used to address RDS encoders. Details related to the coexistence of the ASCII and UECP protocols on the COM0 port are given in the paragraph of this chapter relative to the switching between the ASCII and UECP (UER-SPD490) protocols. WARNING : Do not send the ASCII characters chr$(254) or chr$(255), to the FMX410 Digiplexer without reason, which in certain conditions, might switch automatically to the UECP (UER-SPB490) protocol. Page 57 sur 87

58 The ASCII instruction set relative to the hardware configuration of the FMX410 Digiplexer ASCII instruction syntax??? DISPLAY=n VER? INP? WELCOME_TEXT = Xxxxx...xxxxx Description of the ASCII instruction FMX410 Digiplexer Display all the hardware parameters of the Digiplexer (those described by the instructions of this paragraph). Display all the RDS parameters of the Digiplexer (those described by the instructions figuring in the chapter «Use of RDS by the Digiplexer». Adjust the brightness of the 10 digit display from minimum (n=1) to maximum (n=5). Value saved in permanent memory. Send the version of the Digiplexer internal software. Send "DIGITAL" if the digital input is used for broadcasting, "ANALOG" if the analogue inputs are used. String of characters sent on the powering up of the Digiplexer FMX410 only. The message is sent to the following peripherals : On COM0 : the message written under WELCOME_TEXT is sent in place of the usual welcome message On the DISPLAY : the message written under WELCOME_TEXT is sent as well as the usual message. WELCOME_TEXT is useful as much for the personalising the equipment as for the initialisation of a modem at power up. The message may be erased by typing <WELCOME_TEXT=> without any additional string of characters. IMPORTANT: For each initialisation of a modem use the ^M syntax to specify the transmission of a Carriage Return, after each initialisation line. TYPE? KEY=v KEY? v from 0 to 250 Send the Digiplexer type (FMX4nn). This system command is to be used to enter the secret code to unlock the write protection on the parameters stored in the Digiplexer s permanent memory If the code entered corresponds to the Digiplexer s secret code, it sends a "+" and opens access to the commands allowing the parameters to be modified. The unlocking remains active during 60 seconds after the last valid command entered into the Digiplexer. WARNING 3 failed attempts will make the Digiplexer "deaf" to any new command during 18 hours of operation. After this time, you will be given another three attempts. The "KEY?" command displays : 'KEYS NON ACTIVE : 3 trys' if the Digiplexer is locked with a code, 3 attempts remains for entering the code. Page 58 sur 87

59 ASCII instruction syntax Description of the ASCII instruction FMX410 Digiplexer 'ACTIVE KEY' is the Digiplexer is momentarily unlocked but a locking code is programmed. ' ' (no reply) if no locking code is programmed. IMPORTANT If you have lost your secret code, contact your distributor who will give you a password to unlock it. See also : NKEY= NKEY=v v from 0 to 250 This system command defines or modifies the Digiplexer secret code. In order for this command to be active, the secret code needs to have been entered beforehand (KEY=<secret code>). NKEY=0 will inhibit the secret code function and make the Digiplexer permanently accessible : the Digiplexer is delivered in this condition. See also : KEY= STEREO=b b=0 or 1 LVL19=kk.k where kk.k is from 0.0 to 16,0 RDS=b b=0 or 1 LVL57=kk.k where kk.k is from 0.0 to 16.0 LEVEL=vv vv=0 to 1861 PH57=xx where xx=0 or xx=90 DATA=b Where b=0 or b=1 Defines the FM transmission mode, monophonic (STEREO=0) or stereophonic (STEREO=1). This parameter may be reread with the command "STEREO?". Defines the deviation level of the FM pilot subcarrier (19 khz). The level is expressed in khz and not in %. The parameter may be reread with the command "LVL19?". Activates (RDS=1) or deactivates (RDS=0) the generation of the RDS subcarrier. The parameter may be reread with the command "RDS?". Defines the deviation level of the RDS signal (57kHz). The level is to be expressed in khz and not in %. The parameter may be reread with the command "LVL57?". Defines the peak to peak output voltage of the 57kHz signal. This value is obviously linked to the output level of the DIGIPLEXER, it is only valid if LVLO=12 (output level = +12dBu). Note : this command interact with the command LVL57= LEVEL=465 <=> LVL57=4 Defines the relative phase of the 19kHz and 57kHz subcarriers (derived). The parameter may be reread with the command "PH57?". DATA=0 inhibits the transmission of any RDS data and sends only successive "0"s. This transmission mode remains compatible with all RDS detectors that will detect and announce nevertheless the presence of a valid RDS "signal". LVLO=sdd.d Sdd.d from DATA=1 transmit RDS normally. The DATA parameter is always reset to 1at the power up of the Digiplexer and after being set to 0 for more than 1 minute. Sets the nominal output level in dbu. Corresponds to a deviation of 75 khz at f=400hz in mono without RDS. The parameter may be reread with the command "LVLO?". Step : 0,5 db Page 59 sur 87

60 ASCII instruction syntax to NMPA=sdd.d Sdd.d from to NMPN=sdd.d sdd.d from 0 to GAIN=sdd.d Sdd.d from to AES_EBU= b b=0 or b=1 P_EMPH=nn n=0, 50 or 90 SYNC_IO=n n=i (I) or n=o (O) SYNC=xxx xxx=int or xxx=ext BYPASS=b b=0 or b=1 Description of the ASCII instruction FMX410 Digiplexer Sets the input sensitivity. Example : set NMPA to 12 if the nominal signal level applied is +12dB. The parameter may be reread with the command "NMPA?". Step : 0,5 db Sets the audio digital sensitivity input. "NMPN?" for reading the parameter. Step : 0,5dB. Usual value : -4dBfs (db full scale). Sets the bypass gain of the «MPX» input to the MPX output, unit = db. The parameter may be reread with the command "GAIN?". Forces (b=0) the analogue inputs to be used as audio sources. With b=1, the Digiplexer opts for the digital input when a valid digital-audio signal is applied. The parameter may be reread with the command "AES_EBU?" Selects the type of pre-emphasis to apply to the audio signal : Europe xx=50(µs), USA xx=75(µs), No pre-emphasis xx=0. ). The parameter may be reread with the command "P_EMPH?" Defines the sense of the SYNC port, x=i (Input) for "synchronisation input", x=o (Output) for "synchronisation signal output". ). The parameter may be reread with "SYNC_IO?". Defines if the Digiplexer provides the 19 khz clock in master mode (SYNC=INT) or if it must lock in phase with an external 19 khz synchronisation signal (SYNC=EXT). ). The parameter may be reread with the command "SYNC?". Activates the BYPASS relay function. Normal operation : b=0. The parameter may be reread with the command "BYPASS?". B=1 identical effect to the Digiplexer powered off. Page 60 sur 87

61 ASCII instruction syntax TESTn=xxxx TEST=0 n from 0 to 4 xxxx= L,R or xxxx=l,-r or xxxx=l,0 or xxxx=0,r SPEED=vvvv vvvv =1200 or 2400 or 4800 or 9600 Description of the ASCII instruction FMX410 Digiplexer Test modes. For more details, see the paragraph devoted to the detailed description of this mode. «To transmit the test signals». This command, only valid for the FMX410 Digiplexer, sets up the speed of the communication port. The parameter is stored in permanent memory. A change of speed occurs immediately after the receipt of the instruction. ECHO=b b=0 or b=1 This command determines if the Digiplexer sends an echo(echo=1) of each character, or not (ECHO=0), that it receives by the RS232 interface when in ASCII mode.. ECHO=1 : the characters received are sent back by the Digiplexer s COM0 port. When the Digiplexer has switched into " UECP protocol ", the parameter ECHO=1 activates the sending of a response to each UECP (UER- SPB490) protocol command received (MODE 2 of the UECP) See also : chapter devoted to the UECP (UER-SPB490) protocol commands. PROCESS=b b=0 or b=1 AGC=b b=0 or b=1 GATE=n n=-50 to n=-10 ATTACK=n n=1 to n=99 DECAY=n n=1 to n=99 b=1 allows the use of the CLIP, ADDPWR, SEFFECT. b=0 inihibits all these functions. When b=0 lthe acces to these functions via the menu GotoProces is impossible. Activates (b=1), desactives (b=0) the fonction AGC. This function allows an automatical correction of the input level function of a measurement done on the signal input level. The operation of the AGC is defined with the parameters GATE, ATTACK, DECAY. This function grants an optimal result if CLIP=75. Note : the fonction AGC is active only if PROCESS=1 n defines the threshold of the audio input level below which the AGC function is frozen. This parameter avoids a growth of the audio signal level during an audio drop-out. Defines a rection time for the AGC function during a growth of the input audio signal. n=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 corresponds to 20s/dB Defines a rection time for the AGC function during a growth of the input audio signal. n=1 corresponds to a fast reaction : 0.2s for a drop of 1dB ; nn=99 Page 61 sur 87

62 ASCII instruction syntax CLIP=n n=60 to n=99 or n=off ADDPWR=n n=0 to n=5 SEFFECT=an a= - or a= + n=0 à n=9 PROTECT=b b=0 or b=1 SAVE>USER1 SAVE>USER2 REST<USER1 REST<USER2 REST<FACTY Or INIT410 HELP Description of the ASCII instruction FMX410 Digiplexer corresponds to 20s/dB Defines the maximum deviation level. The signal is clipped by a digital signal process, in order to never overtake this limit. Note : the function CLIP is only active if PROCESS=1 This function allows, thanks to a digital signal processing operation, to densify the audio signal for increasing its 'MPX power' of n db. This function grants an optimal result if CLIP=75. n=0 desactivates this function. Note : the function ADDPWR is only active if PROCESS=1 If a=+, SEFFECT increase the stereo effect. If a= -, SEFFECT drops down the L-R of the MPX signal from 10% if n=1 to 90% if n=9. n=0 inhibits this function. Note : the function SEFFECT is only active if PROCESS=1 b=1 activactes the protection of the Digiplexer configuration for the access via the Digiplex software. b=0 cancels all protection. Store the current configuration, including the RDS parameters of the FMX410 Digiplexer (broadcast) in the memory USER1. Store the current configuration, including the RDS parameters of the FMX410 Digiplexer (broadcast) in the memory USER2 Assign all of the parameters (including RDS for the FMX410 Digiplexer only) stored in the memory USER1 to the current configuration (broadcast). Assign all of the parameters (including RDS for the FMX410 Digiplexer only) stored in the memory USER2 to the current configuration (broadcast). Assign all of the factory predefined parameters (including RDS) to the current configuration (broadcast),. Send back the instruction syntax essential to the ASCII protocol. Page 62 sur 87

63 To use the Digiplexer with the PC software supplied The Digiplexer is delivered with a diskette containing 2 configuration utilities operating under Windows: "DIGIPLEX" configuration software Digiplexer RDS parameter configuration software Place the diskette in drive A : In the Windows 3.x programme manager choose the option File and then Execute... A:\INSTALL.EXE or Click on the Start key for Windows 95, then choose Execute... A:\INSTALL.EXE In the dialogue box that appears, choose the button "search...", select drive A. Type install.exe after "File name", double click below and press OK in the "execute" dialogue window. Follow the instructions that appear on the screen. 2 principle icons will be created: - An icon with the RDS logo, corresponding to the RDS configuration utility - An icon representing the Multiplex spectrum, corresponding to the Digiplexer configuration utility NOTE : You may distribute and copy the software as much as you want, without the specific authorisation of AUDEMAT-AZTEC. Page 63 sur 87

64 To use the «DIGIPLEX» software to configure the Digiplexer hardware General parameters of the Digiplexer (memories, users, password, selection and adjustments of the communication : RS232, INTERNET, Modem) Access to the utility software for the DSP's. Configures all the parameters influencing the behaviour of the Digiplexer in relation to the physical signals (inputs, outputs) :rf following paragraphs. Access to the uploading function of the RDS40 board in its Flash memory. Allows the update of the firmware or the changes of the RDS40 board function : RDS ODA / RDS EPP. Possibility to display the instantaneous peak to peak level and the signal Multiplex power generated by the Digiplexer. It also allows to display and adjust on the same curve the action of the parameters CLIP, AGC, ADDPWR and SEFFECT. Broadcasts the Digiplexer s test signal ; different signal frequencies, different modes (L,R,L+R, L-R). To leave the programme. Page 64 sur 87

65 DIGIPLEX software : General set up screen (F2) Choice of the communication mode : RS232, Modem or Internet and the password. Seting of the IP address and the number of the logical port Configure here the communication port of the PC. Test COM : checks which ports of the PC are likely to be free. Modem Configuration : acces to the modem configuration editor. Update of the DSP firmware : additionnal informations are delivered by AZTEC. ASCII terminal : open the ASCII window : see below. About AZTEC : displays the team of AZTEC with the associated names and phone numbers. Close ; close this window and returns to the main menu. This menu performs the transfer of configurations between the Broadcast memory and the backup memories (MEM1, MEM2 and Factory). Simply slide one coloured element to another to initiate the transfer. This window communicates directly with the Digiplexer by means of it s ASCII protocol instruction set. Type the instructions in the OUTPUT window, the responses sent back by the Digiplexer are displayed in the INPUT window. It is possible to setup the communication speed and to clear the Digiplexer buffer (Clear input Buffer). "Force to ASCII Mode" switches the Digiplexer into ASCII mode, if the EBU protocol is activated ; the ASCII protocol retakes control after several minutes. NOTE : All the ASCII instructions supported by the Digiplexer, including that concerning RDS may be entered in this window. Page 65 sur 87

66 Parameter configuration screen related to the signals used or generated by the Digiplexer (F3). Subcarriers levels Pilot (LVL19) RDS (LVL57) and "High Speed " can be adjusted here. Selection of the different element of the Multiplex signal. Each element can be individually activated or desactivated Select here if the AES/EBU input must have priority (Digital/analogue) or not (Analog only) over the analogue input. Select here the pre-emphasis mode (PRE_EMPH), When the «BYPASS» check box is activated, the BYPASS relay sends the signal applied to the Digiplexer input directly to the output. (BYPASS=1). Download Digiplexer : read and displays the Digiplexer configuration. Upload Digiplexer : send the configuration to the Digiplexer Read data file: load and displays the configuration included in a file Save as: save the displayed configuration in a file of the hard disk of your PC. Selection of the configuration mode. By default, if the PC is connected to the Digiplexer, the mode of configuration is the connected mode : any modification done in this window is immediately sent to the Digiplexer. Action on this button initialise the disconnected mode, then the button diplays 'Disconnection'. The modifications are not transmitted to the Digiplexer. With this mode, you can work on a file. Densification of the Multiplex power of the signal Adjustment of the L-R part of the Multiplex signal. Adjustment of the clipping function. SYNC_IO : defines if the SYNC port is used as a signal input or output. SYNC : defines if the Digiplexer 19 khz clock is Master (INT) or Slave (EXT). Setting of the AGC function Non activation threshold : GATE Audio attack time : ATTACK Audio decay time : DECAY NMPA : defines the nominal operating level of the analogue Digiplexer input in dbu. NMPN : defines the nominal operating level of the digital Digiplexer input in dbfs. LVLO : defines the maximum output level for 75kHz excursion. MPX gain : retransmission gain of a signal from the MPX input to the MPX output. PH57 : defines if the relative phase of the 57kHz (RDS) signal is 0 or 90 in relation to the 19kHz sinusoidal pilot signal. To close this window. Page 66 sur 87

67 Logiciel DIGIPLEX : generating signal test Broadcasts test signal with this window. With this button table, select the signal frequency combined with the type of the test signal. Activation of the test signal only for a temporary period. Indicates the active signal. Closes the window and returns to the main menu. Aknowledgement window is displayed if a test signal is active. DIGIPLEX software : Digital Multiplex signal display IMPORTANT : the displayed levels do not depends of the LVLO parameter. NOTE : the screen refreshing, and in consequence the delay between the audio signal and its picture depends of the processing capacity of your PC. The buffer gives an indication of this delay. Indicates the action of the Clipper. Indicates the action of the AGC function. Value of the MPX power. Close this window and return to the main menu. Acces to : AGC, CLIP, ADDPWR and SEFFECT parameters. State of the PC input buffer. Page 67 sur 87

68 To Configure the RDS parameters with the "FMB10CFG" software (Windows ) For more details concerning RDS configuration and the parameters, refer to the following chapter. The FMB10CFG program is installed automatically during the execution of the installation of the Digiplex set up program. To set up the RDS parameters by modem, use the ASCII terminal (ASCII protocol commands) integrated in the DIGIPLEX software, instead of this set up window. Page 68 sur 87