ANALOG COMMUNICATION

ANALOG COMMUNICATION TRAINING LAB Analog Communication Training Lab consists of six kits, one each for Modulation (ACL-01), Demodulation (ACL-02), Modulation (ACL-03), Demodulation (ACL-04), Noise power spectral density measurement (ACL-05) & FDM (ACL-06). ACL-01 and ACL-02 covers extensively SSB and DSB Modulation and Demodulation techniques. Students are exposed to the concepts of RF and Microphone Amplifiers, Signal Generation, Audio Preamplifier, Voltage Controlled Oscillator, Balanced Modulators, IF Filters, Ceramic Filters, Envelope Detector, Mixers, Output Amplifier, Selective Amplifier, Diode Detectors, Product Detectors, AGC and Audio Amplifiers. ACL-03 and ACL-04 covers the principles & techniques of Modulation and Phase Modulation. ACL-05 covers signal to noise, noise power, noise power spectral density and noise figure measurements ACL-06 covers DSB FDM transmission & reception. These kits are provided with extensive test points allowing students to investigate the various aspects of system operation. Each kit is equipped with correlated courseware to guide students through the application and demonstration of communication techniques and concepts. An interactive user-friendly e-manual software is provided optionally with this training lab on CD. ACL - 01 AMPLITUDE MODULATION TRANSMITTER KIT ACL-01 has an on-board Audio Oscillator as an Analog signal source, which is used as a modulating signal. Alternatively facility is also provided for connecting an external audio-frequency signal as modulating input signal. On-board Double-Sideband Modulator is provided to generate a Double Side Band AM signal with a carrier frequency upto 1.5MHz. Also, on-board Single-Side Band Modulator is provided to generate a Single- Side Band AM signal with the help of Band Pass Filter. These modulated signals may be relayed to ACL-02 either by means of screened cable or the on-board antenna. On-Board Audio Oscillator. Modulation. Double Sideband AM Generation. Single Sideband AM Generation (USB/ LSB). Colpitt s Oscillator VCO Audio Pre-Amplifier. Ceramic Filter. On- Board Antenna. Sine Wave Generator: : 100Hz to 10KHz. : 0 to 2 Vp-p. Audio Input: Audio Pre-amplifier with Microphone and with adjustable output level. VOLTAGE CONTROLLED OSCILLATOR : Output Signal : Sine Wave. : 1) 400KHz to 500KHz. 2) 400KHz to 1500KHz : 0 to 2Vp-p. Output Impedance : 50 Ohm. COLPITT S OSCILLATOR: : 1MHz. : 0 to 2 Vp-p. AM/ DSB/ SSB MODULATOR :(Balance Modulator 1 & 2) Modulation : Modulation. : Double Side Band. : Single Side Band (USB, LSB) Carrier Input : 1-1000 KHz. Modulating Input : 0.1-100 KHz. Carrier Null : Adjustable. Output : Adjustable. BAND PASS FILTER: Central Bandwidth : 10 KHz +/- 3KHz. CERAMIC FILTER: Central Bandwidth : 10 KHz +/- 3KHz. OUTPUT AMPLIFIER: Range : 600 KHz to 1650 KHz. Gain : Adjustable TRANSMITTING MEDIA: Telescopic / MW Coil Antenna and via cable. TEST POINTS: 17 Nos. Test points are provided on board to observe SWITCH FAULTS: 4 Switch Faults are provided on-board to study INTERCONNECTION : 2 mm Banana Socket. POWER SUPPLY : GND, +5V, +12V, -12V. (Dual output terminals) Study of Double Sideband AM Generation. Study of Single Sideband AM Generation. Study of adjustment of Transmitter tuned circuit. Voice transmission with DSB/SSB AM Transmission. Effect of : 14 Nos. : 04 Nos. : 02 Nos. 21

Extra Jumper Caps Microphone & Headphone Power Supply Double Connector : 03 Nos. : 01 No ACL - 02 AMPLITUDE DEMODULATION RECEIVER KIT ACL-02 is a Superheterodyne Receiver with two on-board detectors, an Envelope Detector for Demodulation of Double Side-Band AM signal and a Product Detector for demodulation of Single Side Band AM signal. ACL-02 is capable of receiving and demodulating the Single-Side Band and Double-Side Band transmitted from ACL-01. ACL-02 can also receive Double-Side Band AM broadcast signals in the AM wave band. Super-Heterodyne AM Receiver with AGC. RF Amplifier. Beat Oscillator Mixer. st nd 1 IF and 2 IF Amplifier. Envelope Detector. Product Detector. Audio Amplifier. Reception of AM Signal via Antenna. Superheterodyne Receiver: Intermediate Inputs Output IF RF AMPLIFIER: Range Gain : 400KHz to 1.5MHz. : RF signal. : 455KHz adjustable. : 600 KHz to 1650 KHz. : Adjustable BEAT FREQUENCY OSCILLATOR : Adjustable from 400 to 500 KHz with center frequency of 455 KHz Level 0 to 2 Vp-p st nd 1 IF and 2 IF AMPLIFIER: Central Load Impedance Gain : Variable R-L-C. : Automatic Gain Control. Gain - 43dB DIODE ENVELOPE DETECTOR: Detection of the positive and negative envelope with variable RC filter DSB. PRODUCT DETECTOR: AUDIO OUTPUT: Amplifier with Headphone. Audio Amplifier Gain : Adjustable from 400KHz to 500KHz SSB. : 20dB. RECEIVING MEDIA: Telescopic / MW Coil Antenna and via cable. INTERCONNECTION : 2 mm Banana Socket. SWITCH FAULTS: 4 Switch Faults are provided on board to study TEST POINTS: 19 Nos. Test points are provided on board to observe POWER SUPPLY: GND, +5V, +12V, -12V. Study of Double Sideband AM reception using Envelope Diode Detector. Study of Single Sideband AM reception using Product Detector. Study of Image Frequencies. Study of Sensitivity and Selectivity of Receiver. Study of adjustment of receiver tuned circuits. Voice reception using DSB/ SSB AM receiver (Superheterodyne Receiver). Effect of Uses accessories provided with ACL-01 ACL - 03 FREQUENCY MODULATION TRANSMITTER KIT Mixer ( Converter): Dual Gate MOSFET Input : Local Osc. & RF Output : 455KHz adjustable FI Filter : Dual Tune LC. LOCAL OSCILLATOR: Output Signal Output Impedance : Sine wave : From 900KHz to 2.1MHz. Gang Tunned : Adjustable from 0 to 2Vp-p. : 50 Ohm. 22

ACL-03 has on-board Audio Oscillator as an Analog signal, which is used as a modulating signal. Alternatively facility is also provided for connecting an external audio-frequency signal as modulating input signal. In ACL-03, Modulation is performed by the Varactor Modulator circuit and Phase Modulation is performed by FET amplifier with resonant load. Waveforms resulting from the above modulators are passed onto Mixer/ Amplifier circuit, which amplifies the signal by an adjustable amount. On-board Synchronous Function Generator. FM Modulator Varactor Modulator. Reactance Modulator FM via PM. Pre-Emphasis PM Modulator. Mixer. Audio Pre-Amplifier. SYNCHRONOUS FUNCTION GENERATOR: Waveforms : Sine, Triangular, Square. : 0 to 2Vp-p variable. : 1) 1Hz to 10Hz. 2) 10Hz to 100Hz. 3) 100Hz to 1KHz. 4) 1KHz to 10KHz. 5) 10KHz to 100KHz. POWER SUPPLY: GND, +5V, +12V, -12V. (Dual output terminals) Study of Varactor Modulator. Study of Reactance Modulator. Study of Modulation via Phase Modulator. Study of Pre-Emphasis Circuit. Study of Phase Modulation. Voice Transmission on various modulation methods. Effect of Extra Jumper Caps Microphone Headphone Experimental Manual Circuit Description Manual Power Supply Double Connector : 14 Nos. : 04 Nos. : 04 Nos. : 03 Nos. : 01 No ACL - 04 FREQUENCY DEMODULATION RECEIVER KIT AUDIO INPUT: Audio pre-amplifier with microphone. Gain: 20dB Adjustable output level. FM MODULATOR: 3 Nos. Varactor Modulator with carrier frequency adjustment, Reactance Modulator : Adjustable from 400KHz to 500KHz : 0.1Vp-p FM via PM. : Adjustable from 400KHz to 500KHz. : 0.1Vp-p with integration circuit for indirect frequency modulation. PM MODULATOR: Pre-Emphsis Circuit : Adjustable from 400KHz to 500KHz. :0.5Vp-p with integration circuit for indirect frequency modulation : Time period of 50uS. MIXER (FREQUENCY CONVERTER) : Dual gate MOSFET Inputs : Local oscillator and RF signal. Output IF : 455KHz Adjustable. FI Filter : Dual Tune LC. Transmitter Output : 455KHz frequency. SWITCH FAULTS: 4 Switch Faults are provided on board to study INTERCONNECTION: 2 mm Banana Socket. TEST POINTS: 19 Nos. Test points are provided on board to observe ACL-04 facilitates students to learn a wide variety of demodulator circuits like : Quadrature Detector, Foster-Seeley Detector, Ratio Detector, Phase- Locked Loop Detector, Detuned Resonance Detector. Demodulator: Foster Seeley Detector. Ratio Detector. Phase Locked Loop Detector. Quadrature Detector. Detuned Resonance Detector. De-Emphasis Limiter. Low Pass Filter. Audio Amplifier. 23

FOSTER-SEELEY DETECTOR: : Adjustable from 400KHz to 500KHz. ACL - 05 NOISE POWER SPECTRAL DENSITY KIT RATIO DETECTOR: : Adjustable from 400KHz to 500KHz. PHASE LOCK LOOP DETECTOR: : Adjustable from 400KHz to 500KHz. PHASE DETECTORAND FM QUADRATURE DETECTOR: : Adjustable from 400KHz to 500KHz. DETUNED RESONANCE DETECTOR: : Adjustable from 400KHz to 500KHz. De-Emphsis Circuit : Time period of 50uS. AMPLITUDE LIMITER: Output Limited LOW PASS FILTER: th 4 Order Butterworth Filter. Cut-Off AUDIO OUTPUT: Amplifier with speaker. Audio Amplifier Gain Foster Seeley detector. : From 0.5to 5Vp-p. : 1.5Vp-p. : 3.4KHz. : 20dB. SWITCH FAULTS: 4 Switch Faults are provided on board to study INTERCONNECTION: 2 mm Banana Socket. TEST POINTS: 18 Nos. Test points are provided on board to observe POWER SUPPLY: GND, +5V, +12V, -12V. Study of FM demodulators. Ratio detector. Phase locked loop detector. Quadrature detector. Detuned Resonance Detector. Study of Phase Demodulator. Study of De-Emphsis Circuit. Study effect of Pre-Emphasis and De-Emphasis on FM Demodulator. Voice reception by various demodulation methods. Effect of Uses accessories provided with ACL-03 ACL-05 kit allows students to understand the noise effect in Analog circuits and in AM/FM communication system. With this kit students can measure noise power spectral density. 7-Segment display provided onboard shows power of the signal applied to it. Pseudo Random Noise Generator S/N Ratio Noise Figure Power Spectral Density Low Pass Filter Switch Faults CLOCK GENERATOR: ONBOARD SIGNAL: Sine Wave: : 2MHz : 1 to 10 KHz. : 0 to 2Vpp. NOISE GENERATOR: Pseudo Random Noise Source: Number of Bits : 32 bit. Output : 0 to 1V. Noise Bandwidth : 2 MHz. SIGNAL ATTENUATION AND ADDER: Adjustable from 0 to the maximum of input value. Signal + Noise Adder Stage. LOW PASS FILTER: th 4 Order Butterworth Filter Cut-off : 3.4KHz. POWER METER AND DISPLAY: Input signal : 0 to 2Vpp. Timer : 1 to 15 seconds. Display : 2 Digit Seven Segment SWITCH FAULTS: 4 Switch Faults are provided on board to study INTERCONNECTION: 2 mm Banana Socket. 24

TEST POINTS: 16 Nos. Test points are provided on board to observe POWER SUPPLY: GND, +5V, +12V, -12V. Observe the effect of Noise on various analog systems. Calculate Signal to Noise Ratio. Calculate Noise Figure. Calculate Noise Power and Noise Power Spectral Density. Effect of Low pass Filter on Noisy signal Effect of Experimental Manual Circuit Description Manual Power Supply : 08 Nos. : 02 Nos. : 02 Nos. ACL-06 FDM TRANSMITTER / RECEIVER TRAINER KIT Carrier Generator : Subcarrier : 1 KHz to 20 KHz and 1 KHz to 30 KHz with adjustable amplitude of 0-2 Vp-p Pilot carrier : 256 KHz Transmitter : High frequency transmission using DSB Multiplexing : Division Multiplexing Channel : 02 Nos. Band Pass Filter : Band pass filter Pass Band : Filter 1 & 3 frequency range 7 to 11 KHz with fc 9 KHz Filter 2 & 4 frequency range 16 to 20 KHz with fc 18 KHz AM/ DSB MODULATOR: Modulation : Modulation. : Double Side Band. Receiver : Demodulation of DSB Demultiplexing : Division Demultiplexing th Low pass filter : 4 order butterworth filter Switch Faults: 8 Switch Faults are provided on board to study different effects on circuit. Interconnection: 2 mm Banana Socket. Test Points: 25 Test points are provided to observe various intermediate signals. Power Supply : GND, +5V, +12V, -12V. To study frequency response of band pass filters Study of DSB Modulation To study the operation of frequency division multiplexing Study of DSB Demodulation To study the operation of frequency division demultiplexing To study effect of out of band signaling To study effect of switch faults To study voice communication through FDM (Optional) ACL-06 is an analog communication trainer kit designed to study the fundamentals of frequency division multiplexing using DSB modulation technique. Using this module students can well understand the basics of the Balance Modulator, Band Pass Filters, Demodulators and division multiplexing and demultiplexing techniques. Onboard Clock generator Onboard Carrier wave generator 2 channel FDM communication system DSB AM Modulator DSB AM Demodulator Band Pass Filters Low Pass Filters Out of Band signal transmission Voice Communication (optional ) Switch Faults Experimental Manual Circuit Description Manual Power Supply : 10 Nos. : 03 Nos. : 02 Nos. FG-01 Function Generator A I/O Audio Input Output Kit 25

ADVANCE ANALOG COMMUNICATION TRAINING SYSTEM Advance Analog Communication Training System, is a complete range of Analog Communication kits in a modular fashion. Every stage and phase achieved in the process of modulation and demodulation is demonstrated. One of the most salient features of the kit is the capability to observe & analyze DSB-USB-LSB and FM signal spectrum on a Dual Trace ACT - 01 SIGNAL GENERATOR AND FREQUENCY MODULATION KIT Oscilloscope. One look at the list of experiments at the end of this section is sufficient to understand the depth at which these kits will take the students, to understand the principles of Analog Communication and its operating characteristics. An interactive user-friendly e-manual software is provided optionally with this training system on CD. ACT - 03 AMPLITUDE DEMODULATION KIT ACT-01 forms the heart of the system, generating all necessary signals for performing various experiments in Analog Communication, which includes all modulating and carrier signals. On-board Function Generator. Voltage Controlled Oscillator. Modulator Audio Pre-amplifier. Sweep Generator. RF detector.. ACT - 02 AM / DSB / SSB KIT ACT-03 allows students to understand the functioning and operation of Demodulation using two stage Intermediate Amplifier and Diode Envelope Detector. This kit is also useful for the study of AGC, Mixer with dual-tuned LC. Converter (Mixer). st nd 1 IF & 2 IF Amplifiers. AM-Diode Detector. Low Pass Filter. Automatic Gain Control. ACT - 04 FREQUENCY DEMODULATION AND PHASE MODULATION KIT ACT-02 allows students to understand the functioning and operation of Balanced Modulator, modulation with DSB/ SSB, Ring Modulator, Ceramic filter, Tunable filter & Low Pass Filter technique. AM Generator. DSB, DSB-SC.SSB. Balanced Modulator. Ring Modulator. Ceramic Filter. Tunable Filter. Low Pass Filter. ACT-04 allows students to understand the functioning and operation of Demodulation concept. This kit also explains the working of Phase Modulation and Demodulation concept. Phase Modulator. Limiter. Automatic Control. Foster Seeley & Ratio Detector. Product Detector / Quadrature Detector. 26

ACT - 05 FILTER / NOISE / AUDIO AMPLIFIER KIT Balanced Modulator: 2 Nos. of Balanced modulator for DSB/ SSB Modulation. Carrier Input : 1KHz - 900 KHz. Modulating Input : 0.1KHz - 100KHz. Carrier Null : Adjustable. Output Impedance : Adjustable. RING MODULATOR: Diode Balance Modulator with AM DSB carrier (USB & LSB). Carrier Input : 4KHz - 20KHz. Modulating Input : 0.1KHz - 4KHz. ACT-05 kit allows students to understand the noise effect in audio circuits and in communication system. Noise Generator S/N Ratio Noise Figure Matched T & PI, High Pass, Band Pass & Band Reject Filters Audio Amplifier Switch Faults ON-BOARD FUNCTION GENERATOR: Waveforms : Sine, Triangular, Square. : 0 to 2 Vp-p. : 100Hz to 10KHz. Synchronous Square Wave : X4 & 1/4 of the main output signal, Adjustable. VOLTAGE CONTROL OSCILLATOR: Carrier Generator Modulator: A. VCO1: : 400KHz to 1500KHz. 400KHz to 500KHz. : Variable 0 to 2 Vp-p. Inputs to VCO1 : Modulating signal, Marker, AFC (Automatic Control). B. VCO2 : : 400KHz to 1500KHz. : Variable 0 to 2 Vp-p. Input to VCO2 : Modulating signal. AUDIO PRE-AMPLIFIER: Audio Input : Microphone. Input Impedance : 600 Ohms. Voltage Gain : 1 to 100. RC Filter : 3.4 KHz cut-off. SWEEP GENERATOR: Sweep Sweep Depth Output for Oscilloscope SPECTRUM DETECTOR: Minimum Input Input level : 10Hz. : Adjustable. : X- axis. : 100mVp-p : Adjustable CERAMIC FILTER: Central Bandwidth TUNABLE FILTER: Central Detector Type LOW PASSACTIVE FILTER: Cut off : 3.4KHz. : 10KHz, +/- 3KHz (Adjustable). : Adjustable from 2 to 8KHz. : Diode envelope. FREQUENCY CONVERTER (MIXER): Inputs : Local Oscillator and RF Signal. Output Intermediate Freq. : 455KHz Adjustable. IF Filter : Dual tuned LC. Dual-Gate MOSFET : To mixup RF & LO st nd 1 & 2 STAGE IF AMPLIFIER: Central : 455KHz Adjustable. Load Impedance : Variable R-L-C. Gain : 40 db. Impedance Matching with Transformer & Auto-transformer. DIODE ENVELOPE DETECTOR: Detection of the positive or negative envelope with variable R-C filter. AUTOMATIC GAIN CONTROL: Output can be controlled in case of maximum input signal. PHASE MODULATOR: Modulation Technique : FET amplifier with resonant load. : 400KHz to 500KHz. LIMITER: : From 0.5 to 5Vp-p. Output : 1.5Vp-p Max. AUTOMATIC FREQUENCY CONTROL: of FM Modulator can be controlled with integrative effect. FOSTER-SEELEY DEMODULATOR: : 400KHz to 500KHz. RATIO DETECTOR: : 400KHz to 500KHz. PHASE DETECTOR & FM QUADRATURE DETECTOR: Phase Shifter, Product Detector & RC Filter. 27

: 400KHz to 500KHz. NOISE GENERATOR : White Noise Source Output : Adjustable from 0 to 3Vp-p. SIGNAL ATTENUATION NETWORK: Adjustable from 0 to the maximum of input value. Signal + Noise Adder Stage. AUDIOAMPLIFIER WITH SPEAKER: Output Power : 0.5W. Speaker : 8 Ohms, 0.3W. FILTERS: 4 Nos. High Pass Filter : 3.4KHz cutoff. Band Pass Filter : Freq. range 7 to 13KHz. Band Reject Filter : Freq. range 7 to 13KHz. Matched Filter: PI Section : 20KHz cutoff. T Section : 20KHz cutoff. Input Voltage : 0 to 2 Vpp Output Voltage : 0 to 2 Vpp SWITCH FAULTS: 4 Switch Faults are provided on-board to study INTERCONNECTION: 2mm banana socket. TEST POINTS: 20 Nos. Test points are provided on-board to observe POWER SUPPLY: GND, +5V, +12V, -12V. ACCESSORIES FOR ACT-01 TOACT-05: Microphone Speaker Tunning Tool Jumper Caps Experimental Manual Circuit Description Manual Power Card Power Chords Power Supply : 26 Nos. : 12 Nos. : 10 Nos. : 11 Nos. : 05 Nos. LIST OF EXPERIMENTS USING ACT-01 TOACT-05: AMPLITUDE MODULATION: a. Study the operation of an Modulator. b. Calculate modulation index of an Modulated wave. c. Observe linearity curve of the Modulator. d. Observe spectrum of the AM Signal. AMPLITUDE DEMODULATION: a. Study and observe the operation of Envelope Detector. b. Study and observe the effect of time constant RC. c. Study and observe the operation of synchronous AM Detector. SINGLE SIDE BAND MODULATION (SSB): a. i) Observe frequency response of ceramic filter. ii) Plot the frequency response curve of ceramic filter. b. Study the operation of Modulator with suppressed carrier. c. Study Single Side Band Generation. d. Study and observe spectrum of the signal generated by the Balance Modulator. e. Study demodulation of the SSB Signal. f. Study demodulation of the Ring Modulator. FREQUENCY MODULATION: a. Plot modulation characteristics of Modulator. Calculate modulation sensitivity of Modulator. Calculate Non-linearity of Modulator. b. Observe and measure frequency deviation and modulation index of Modulator. c. Study marker insertion to evaluate the Deviation. d. Observe spectrum of the FM signal. FREQUENCY DEMODULATION: a. Plot demodulation characteristics of the frequency demodulator (Foster Seeley Demodulator). i) Calculate demodulation sensitivity and non-linearity of Demodulator. ii) Observe demodulation characteristics curve iii) Observe waveforms of the demodulated Signal. b. Study of Ratio Demodulator. c. Study of Quadrature Detector. d. Study of Limiter Circuit. PHASE MODULATION: a. Study & observe the waveforms of the Phase Modulated Signal. b. Study & observe the waveforms of Phase Demodulated Signal. c. Study Demodulation via Phase Modulator. FREQUENCY CONVERSION: a. Study frequency relations with the Mixer Study effect of Image. b. Observe the frequency response of IF Filter Plot frequency response of the IF Filter. SELECTIVE AMPLIFIER: a. i) Find the central frequency and bandwidth of an amplifier. ii) Impedance transformation with transformer. iii) Impedance transformation with auto transformer. b. Calibration of gain of a 2 Stage IF Amplifier. c. Automatic Gain Control. d. AM Detector. AM SUPERHETERODYNE RECEIVER WITH AGC. FM SUPERHETERODYNE RECEIVER WITH AFC. CHANNEL AND NOISE: a. Examine the operation of a Noise Generator. b. Examine the operation of a signal attenuation network. c. Measurement of S/N Ratio. d. Measurement of Noise Figure. AUDIO AMPLIFIER: a. Measurement of Response and Power Output. STUDY OF FILTERS. a. High Pass Filter b. Band Pass Filter c. Band Reject Filter d. Matched Filter (PI & T Section) EFFECT OF SWITCH FAULTS. 28