Tone decoder/phase-locked loop

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1 NE/SE DESCRIPTION The NE/SE tone and frequency decoder is a highly stable phase-locked loop with synchronous AM lock detection and power output circuitry. Its primary function is to drive a load whenever a sustained frequency within its detection band is present at the self-biased input. The bandwidth center frequency and output delay are independently determined by means of four external components. PIN CONFIGURATIONS FILTER CAPACITOR C LOW-PASS FILTER CAPACITOR C INPUT SUPPLY VOLTAGE V FE, D, N Packages 7 4 GROUND TIMING ELEMENTS R AND C TIMING ELEMENT R FEATURES Wide frequency range (.Hz to khz) High stability of center frequency Independently controllable bandwidth (up to 4%) High out-band signal and noise rejection Logic-compatible output with ma current sinking capability Inherent immunity to false signals Frequency adjustment over a -to- range with an external resistor Military processing available APPLICATIONS Touch-Tone decoding Carrier current remote controls Ultrasonic controls (remote TV, etc.) Communications paging C NC C INPUT NC 4 TOP VIEW F Package 4 V CC 7 TOP VIEW Frequency monitoring and control Wireless intercom Precision oscillator 9 GND NC NC RC R NC NC BLOCK DIAGRAM 4 R INPUT V PHASE DETECTOR.9k C CURRENT CONTROLLED OSCILLATOR R AMP LOOP LOW PASS FILTER QUADRATURE PHASE DETECTOR V REF AMP 7 FILTER V Touch-Tone is a registered trademark of AT&T. April,

2 NE/SE EQUIVALENT SCHEMATIC R C V 4 R Q Q 7 Q Q R Q D R7 Q Q V Q Q7 A Q9 R4 Q R9 R R Q4 Q Q Q7 Q Q9 B R9 V R R R E F Q Q Q R4 V R R R7 Q Q4 Q Q7 Q Q9 B R R R k Q R Q R Q4 A B R9 C c R Vi R4 R C V Q R Q R Q B R Q Q Q7 Q R7 R9 k Q Vref R7 Q Q9 R R4 R R E R4 k Q4 R4 k C Q R4 Q Q4 R R4 R4 R 4.7k Q Q4 Q Q Q Q7 R4 R49 Q C R4 Q47 Q4 Q4 Q44 F Q4 Q4 Q4 B R44 R4 C RL B Q V Q April, 99 44

3 NE/SE ORDERING INFORMATION DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG # -Pin Plastic SO to 7 C NED 74C 4-Pin Cerdip to 7 C NEF B -Pin Plastic DIP to 7 C NEN 44B -Pin Plastic SO - C to C SED 74C -Pin Cerdip - C to C SEFE B -Pin Plastic DIP - C to C SEN 44B ABSOLUTE MAXIMUM RATINGS T A SYMBOL PARAMETER RATING UNIT Operating temperature NE to 7 C SE - to C V CC Operating voltage V V Positive voltage at input. V S V V- Negative voltage at input - V DC V OUT Output voltage (collector of output transistor) V DC T STG Storage temperature range - to C P D Power dissipation mw April, 99 4

4 NE/SE DC ELECTRICAL CHARACTERISTICS V =.V; T A = C, unless otherwise specified. SYM- BOL Center frequency PARAMETER TEST CONDITIONS SE NE UNIT Min Typ Max Min Typ Max Highest center frequency khz Center frequency stability - to ±4 ±4 ppm/ C Center frequency distribution to 7 ± ± ppm/ C khz - - %. C Center frequency shift with supply voltage Detection bandwidth BW Largest detection bandwidth khz khz..7 %/V. C 4 4 % of. C BW Largest detection bandwidth skew 4 % of BW Largest detection bandwidth V I =mv RMS ±. ±. %/ C variation with temperature BW Largest detection bandwidth V I =mv RMS ± ± %/V Input variation with supply voltage R IN Input resistance kω V I Smallest detectable input voltage 4 I L =ma, f I = mv RMS Output Largest no-output input voltage 4 I L =ma, f I = mv RMS Greatest simultaneous out-band db signal-to-in-band signal ratio Minimum input signal to wide-band noise ratio B n =4kHz - - db Fastest on-off cycling rate / / output leakage current V =V.. µa output voltage I L =ma V I L =ma.... V t F Output fall time =Ω ns t R Output rise time =Ω ns General V CC Operating voltage range V Supply current quiescent 7 ma Supply current activated =kω ma t PD Quiescent power dissipation mw NOTES:. Frequency determining resistor should be between and kω. Applicable over 4.7V to.7v. See graphs for more detailed information.. Pin to Pin feedback network selected to eliminate pulsing during turn-on and turn-off. 4. With R =kω from Pin to V. See Figure. April, 99 4

5 NE/SE TYPICAL PERFORMANCE CHARACTERISTICS Bandwidth vs Input Signal Amplitude (Hz * F) µ Largest Detection bandwidth vs Operating Frequency Detection bandwidth as a Function of and INPUT VOLTAGE mvrms 4 4 BANDWIDTH % OF O LARGEST BANDWIDTH % OF f. CENTER FREQUENCY khz BANDWIDTH % OF Typical Supply Current vs Supply Voltage Greatest Number of Cycles Before Output Typical Output Voltage vs Temperature CUPPLY CURRENT ma NO LOAD ON CURRENT QUIESCENT CURRENT CYCLES BANDWIDTH LIMITED BY EXTERNAL RESISTOR (MINIMUM ) BANDWIDTH LIMITED BY ( ) VOLTAGE PIN V..9. I L = ma I L = ma SUPPLY VOLTAGE V BANDWIDTH % OF TEMPERATURE C Typical Frequency Drift With Temperature (Mean and SD) Typical Frequency Drift With Temperature (Mean and SD) Typical Frequency Drift With Temperature (Mean and SD).. V = 4.7V.. V =.7V.. () V = 7.V () V = 9.V ().. () TEMPERATURE C TEMPERATURE C TEMPERATURE C April, 99 47

6 Philips Semiconductors Linear Products NE/SE TYPICAL PERFORMANCE CHARACTERISTICS (Continued) TEMPERATURE COEFFICIENT ppm/ C Center Frequency Temperature Coefficient (Mean and SD) t = C to 7 C SUPPLY VOLTAGE V t O t O V % V Center Frequency Shift With Supply Voltage Change vs Operating Frequency 4 4 CENTER FREQUENCY khz BANDWIDTH % OF Typical Bandwidth Variation Temperature 4 4 BANDWIDTH AT C 7 7 TEMPERATURE C DESIGN FORMULAS. C BW 7 V I V I mv RMS in % of Where V I =Input voltage (V RMS ) =Low-pass filter capacitor (µf) PHASE-LOCKED LOOP TERMINOLOGY CENTER FREQUENCY ( ) The free-running frequency of the current controlled oscillator (CCO) in the absence of an input signal. Detection Bandwidth (BW) The frequency range, centered about, within which an input signal above the threshold voltage (typically mv RMS ) will cause a logical zero state on the output. The detection bandwidth corresponds to the loop capture range. Lock Range The largest frequency range within which an input signal above the threshold voltage will hold a logical zero state on the output. Detection Band Skew A measure of how well the detection band is centered about the center frequency,. The skew is defined as (f MAX f MIN - )/ where fmax and fmin are the frequencies corresponding to the edges of the detection band. The skew can be reduced to zero if necessary by means of an optional centering adjustment. OPERATING INSTRUCTIONS Figure shows a typical connection diagram for the. For most applications, the following three-step procedure will be sufficient for choosing the external components, C, and.. Select R and C for the desired center frequency. For best temperature stability, R should be between K and K ohm, and the combined temperature coefficient of the RC product should have sufficient stability over the projected temperature range to meet the necessary requirements.. Select the low-pass capacitor,, by referring to the Bandwidth versus Input Signal Amplitude graph. If the input amplitude Variation is known, the appropriate value of necessary to give the desired bandwidth may be found. Conversely, an area of operation may be selected on this graph and the input level and C may be adjusted accordingly. For example, constant bandwidth operation requires that input amplitude be above mv RMS. The bandwidth, as noted on the graph, is then controlled solely by the product ( (Hz), C(µF)). April, 99 4

7 NE/SE TYPICAL RESPONSE INPUT NOTE: = Ω Response to mv RMS Tone Burst saturates; its collector voltage being less than. volt (typically.v) at full output current (ma). The voltage at Pin is the phase detector output which is a linear function of frequency over the range of.9 to. with a slope of about mv per percent of frequency deviation. The average voltage at Pin is, during lock, a function of the in-band input amplitude in accordance with the transfer characteristic given. Pin is the controlled oscillator square wave output of magnitude (V -V BE ) (V-.4V) having a DC average of V/. A kω load may be driven from pin. Pin is an exponential triangle of V P-P with an average DC level of V/. Only high impedance loads may be INPUT (PIN ) 7% 4% BW V CE (SAT) <.V V NOTES: S/N = db = Ω Noise Bandwidth = 4Hz Response to Same Input Tone Burst With Wideband Noise. The value of C is generally non-critical. C sets the band edge of a low-pass filter which attenuates frequencies outside the detection band to eliminate spurious outputs. If C is too small, frequencies just outside the detection band will switch the output stage on and off at the beat frequency, or the output may pulse on and off during the turn-on transient. If C is too large, turn-on and turn-off of the INPUT V V 4 LOW PASS FILTER (PIN ) PIN VOLTAGE (AVG) V REF THRESHOLD VOLTAGE. f =. mvrms IN-BAND INPUT VOLTAGE Figure. Typical Output Response.9V.V.7V C 7 R C LOW PASS FILTER Figure. FILTER output stage will be delayed until the voltage on passes the threshold voltage. (Such delay may be desirable to avoid spurious outputs due to transient frequencies.) A typical minimum value for is. 4. Optional resistor R sets the threshold for the largest no output input voltage. A value of kω is used to assure the tested limit of mv RMS min. This resistor can be referenced to ground for increased sensitivity. The explanation can be found in the optional controls section which follows. AVAILABLE S (Figure ) The primary output is the uncommitted output transistor collector, Pin. When an in-band input signal is present, this transistor April, 99 49

8 NE/SE V R R cause supply voltage fluctuations which could, for example, shift the detection band of narrow-band systems sufficiently to cause momentary loss of lock. The result is a low-frequency oscillation into and out of lock. Such effects can be prevented by supplying heavy load currents from a separate supply or increasing the supply filter capacitor. DECREASE SENSITIVITY R A k R B.k R C.k INCREASE SENSITIVITY SILICON DIODES FOR TEMPERATURE COMPENSATION (OPTIONAL) Figure. Sensitivity Adjust connected to pin without affecting the CCO duty cycle or temperature stability. V DECREASE SENSITIVITY INCREASE SENSITIVITY SPEED OF OPERATION Minimum lock-up time is related to the natural frequency of the loop. The lower it is, the longer becomes the turn-on transient. Thus, maximum operating speed is obtained when is at a minimum. When the signal is first applied, the phase may be such as to initially drive the controlled oscillator away from the incoming frequency rather than toward it. Under this condition, which is of course unpredictable, the lock-up transient is at its worst and the theoretical minimum lock-up time is not achievable. We must simply wait for the transient to die out. The following expressions give the values of and which allow highest operating speeds for various band center frequencies. The minimum rate at which digital information may be detected without information loss due to the turn-on transient or output chatter is about cycles per bit, corresponding to an information transfer rate of / baud. V V V V OPERATING PRECAUTIONS A brief review of the following precautions will help the user achieve the high level of performance of which the is capable.. Operation in the high input level mode (above mv) will free the user from bandwidth variations due to changes in the in-band signal amplitude. The input stage is now limiting, however, so that out-band signals or high noise levels can cause an apparent bandwidth reduction as the inband signal is suppressed. Also, the limiting action will create in-band components from sub-harmonic signals, so the becomes sensitive to signals at /, /, etc.. The will lock onto signals near (n), and will give an output for signals near (4n) where n=,,, etc. Thus, signals at and 9 can cause an unwanted output. If such signals are anticipated, they should be attenuated before reaching the input.. Maximum immunity from noise and out-band signals is afforded in the low input level (below mv RMS ) and reduced bandwidth operating mode. However, decreased loop damping causes the worst-case lock-up time to increase, as shown by the Greatest Number of Cycles Before Output vs Bandwidth graph. 4. Due to the high switching speeds (ns) associated with operation, care should be taken in lead routing. Lead lengths should be kept to a minimum. The power supply should be adequately bypassed close to the with a.µf or greater capacitor; grounding paths should be carefully chosen to avoid ground loops and unwanted voltage variations. Another factor which must be considered is the effect of load energization on the power supply. For example, an incandescent lamp typically draws times rated current at turn-on. This can be somewhat greater when the output stage is made less sensitive, rejection of third harmonics or in-band harmonics (of lower frequency signals) is also improved. R f * k C f *OPTIONAL - PERMITS LOWER VALUE OF C f R A TO k R f k Figure 4. Chatter Prevention LOWERS RAISES V R R A k V RAISES R B.k R C.k Figure. Skew Adjust R A TO k R f k LOWERS RAISES R SILICON DIODES FOR TEMPERATURE COMPENSATION (OPTIONAL) April, 99 4

9 Philips Semiconductors Linear Products NE/SE F F In cases where turn-off time can be sacrificed to achieve fast turn-on, the optional sensitivity adjustment circuit can be used to move the quiescent voltage lower (closer to the threshold voltage). However, sensitivity to beat frequencies, noise and extraneous signals will be increased. OPTIONAL CONTROLS (Figure ) The has been designed so that, for most applications, no external adjustments are required. Certain applications, however, will be greatly facilitated if full advantage is taken of the added control possibilities available through the use of additional external components. In the diagrams given, typical values are suggested where applicable. For best results the resistors used, except where noted, should have the same temperature coefficient. Ideally, silicon diodes would be low-resistivity types, such as forward-biased transistor base-emitter junctions. However, ordinary low-voltage diodes should be adequate for most applications. SENSITIVITY ADJUSTMENT (Figure ) When operated as a very narrow-band detector (less than percent), both and are made quite large in order to improve noise and out-band signal rejection. This will inevitably slow the response time. If, however, the output stage is biased closer to the threshold level, the turn-on time can be improved. This is accomplished by drawing additional current to terminal. Under this condition, the will also give an output for lower-level signals (mv or lower). By adding current to terminal, the output stage is biased further away from the threshold voltage. This is most useful when, to obtain maximum operating speed, and are made very small. Normally, frequencies just outside the detection band could cause false outputs under this condition. By desensitizing the output stage, the out-band beat notes do not feed through to the output stage. Since the input level must R A k V V INPUT VOLTAGE MV RMS.k.9k.4k.9k.k.k 4.k k k k R 4 4 UNLATCH UNLATCH V C A R f k R f k V DETECTION BAND % OF V NOTE: C A prevents latch-up when power supply is turned on. PIN R A k R B R R A R B R B R C R C Figure 7. Output Latching R C OPTIONAL SILICON DIODES FOR TEMPERATURE COMPENSATION NOTE: k R C f R O k R f R O Adjust control for symmetry of detection band edges about. Figure. BW Reduction April, 99 4

10 NE/SE CHATTER PREVENTION (Figure 4) Chatter occurs in the output stage when is relatively small, so that the lock transient and the AC components at the quadrature phase detector (lock detector) output cause the output stage to move through its threshold more than once. Many loads, for example lamps and relays, will not respond to the chatter. However, logic may recognize the chatter as a series of outputs. By feeding the output stage output back to its input (Pin ) the chatter can be eliminated. Three schemes for doing this are given in Figure 4. All operate by feeding the first output step (either on or off) back to the input, pushing the input past the threshold until the transient conditions are over. It is only necessary to assure that the feedback time constant is not so large as to prevent operation at the highest anticipated speed. Although chatter can always be eliminated by making large, the feedback circuit will enable faster operation of the by allowing to be kept small. Note that if the feedback time constant is made quite large, a short burst at the input frequency can be stretched into a long output pulse. This may be useful to drive, for example, stepping relays. DETECTION BAND CENTERING (OR SKEW) ADJUSTMENT (Figure ) When it is desired to alter the location of the detection band (corresponding to the loop capture range) within the lock range, the circuits shown above can be used. By moving the detection band to one edge of the range, for example, input signal variations will expand the detection band in only one direction. This may prove useful when a strong but undesirable signal is expected on one side or the other of the center frequency. Since R B also alters the duty cycle slightly, this method may be used to obtain a precise duty cycle when the is used as an oscillator. ALTERNATE METHOD OF BANDWIDTH REDUCTION (Figure ) Although a large value of will reduce the bandwidth, it also reduces the loop damping so as to slow the circuit response time. This may be undesirable. Bandwidth can be reduced by reducing the loop gain. This scheme will improve damping and permit faster operation under narrow-band conditions. Note that the reduced impedance level at terminal will require that a larger value of be used for a given filter cutoff frequency. If more than three s are to be used, the network of R B and R C can be eliminated and the R A resistors connected together. A capacitor between this junction and ground may be required to shunt high frequency components. LATCHING (Figure 7) To latch the output on after a signal is received, it is necessary to provide a feedback resistor around the output stage (between Pins and ). Pin is pulled up to unlatch the output stage. REDUCTION OF C VALUE For precision very low-frequency applications, where the value of C becomes large, an overall cost savings may be achieved by inserting a voltage-follower between the C junction and Pin, so as to allow a higher value of and a lower value of C for a given frequency. PROGRAMMING To change the center frequency, the value of can be changed with a mechanical or solid state switch, or additional C capacitors may be added by grounding them through saturating NPN transistors. April, 99 4

11 NE/SE TYPICAL APPLICATIONS C 97Hz 77Hz R R DIGIT 4 Hz 94Hz 7 9 9Hz * NOTES: Component values (Typical) =. to kω R = 4.7kΩ R = kω C =.mf =.mf V =.mf V C 4 = µf V Hz 477Hz Touch-Tone Decoder April, 99 4

12 NE/SE TYPICAL APPLICATIONS (Continued) TO V Hz AC LINE pf V RMS C 4 7pF K LOAD :.kω C 74 khz C..4mfd. AUDIO OUT (IF INPUT IS FREQUENCY MODULATED) Precision VLF V Carrier-Current Remote Control or Intercom V k INPUT SIGNAL (>mvrms) f C INPUT CHANNEL OR RECEIVER C V NOR V O f k R C C C (mfd) C C R. R 4% Bandwidth Tone Decoder C C C Dual-Tone Decoder mv (pp) SQUARE OR mvrms SINE INPUT f (INTO k OHM MIN. LOAD) 9 PHASE SHIFT C NOTES: R = / Adjust so that φ = 9 with control midway. NOTES:. Resistor and capacitor values chosen for desired frequencies and bandwidth.. If C is made large so as to delay turn-on of the top, decoding of sequential (f f ) tones is possible. to Phase Shifter April, 99 44

13 NE/SE TYPICAL APPLICATIONS (Continued) CONNECT PIN TO.V TO INVERT VCO TERMINAL (±%) > Ω > Ω k C C L C Oscillator With Quadrature Output Oscillator With Double Frequency Output Precision Oscillator With ns Switching kω VCO TERMINAL (±%) kω kω (MIN) C C C DUTY CYCLE ADJUST Pulse Generator With % Duty Cycle Precision Oscillator to Switch ma Loads Pulse Generator April, 99 4

14 This datasheet has been download from: Datasheets for electronics components.

TONE DECODER / PHASE LOCKED LOOP PIN FUNCTION 1 OUTPUT FILTER 2 LOW-PASS FILTER 3 INPUT 4 V + 5 TIMING R 6 TIMING CR 7 GROUND 8 OUTPUT

TONE DECODER / PHASE LOCKED LOOP GENERAL DESCRIPTION The NJM567 tone and frequency decoder is a highly stable phase locked loop with synchronous AM lock detection and power output circuitry. Its primary