Communication Lab

AMPLITUDE MODULATION AND DEMODULATION KIT 

Amplitude modulation is implemented by means of a variable transconductance four quadrant multiplier designed around CA3086. On board carrier and modulating signals along with power supplies are provided. A detector and a low pass filter are provided to demodulate the signal. Modulation Index, Depth of Modulation, etc., are studied using this trainer.


HARDWARE SPECIFICATION :

• Carrier Generator 100 KHz 
• Modulating signal generatorat 1KHz 
• amplitude modulator 
• amplitudedemodulator 
• Inbuilt Power Supply 
• Enclosed in an ABS plastic cabinet with cover 
• set of 2 mmpatchchords&manual 

Frequency Modulation And Demodulation Kit

Frequency Modulation is accomplished using IC 8038 a function generator IC with built-in VCO. On-board carrier and modulating signal with power supplies are provided. PLL IC 565 is used to demodulate FM signal. Frequency deviation, Modulation Index etc., are studied using this trainer. Frequency deviation, Modulation Index etc., are studied using this trainer.

• carrier generator75 KHz 
• modulating signal genrator10KHz 
• frequency modulation 
• Frequency Demodulator 
• Frequency Demodulator 
• Enclosed in an ABS plastic cabinet with cover 
• Set of 2mm Patch Chords & Manual 

Phase Modulation And Demodulation Kit

• Phase modulation & demodulation 
• Modulating signal generator. 
• Carrier/PM generator (8038) 
• Demodulator (565) 
• ±12V/500mA Fixed DC Power Supply. 
• Assembled in ABS Plastic Box with cover 
• 220V mains operated. 
• Set of patch chords & user manual. 

Pulse Amplitude Modulation & Demodulation Kit

• Built in carrier generator 10KHz 
• Built in modulating signal generator 1 KHz 
• Pam modulation /demodulator 
• Assembled in plastic boxwith circuitprinted 
• Set of patch chords & experimental manaul 
• In bulit power supply 

Pulse Position Modulation & Demodulation Kit

• Built in Carrier Generator 10 KHz 
• Built in AF signal generator 1 KHz 
• PPM Modulator 
• PPM Demodulator 
• Assembled in plastic Box with circuit printed on PCB with 2mm socket for test points & to see the waveforms 
• Set of Patch Chords & Experimental Manual. 
• in bulit power supply 

Amplitude Shift Keying Modulation And Demodulation Kit

• Carrier Generator: 50 KHz - 100 KHz, 5Vp-p 
• Clock Generator : 100Hz - 10KHz 
• Programmable Word Generator : Cyclic 8-Bit Word 
• ASK Modulator 
• ASK Demodulator 
• Assembled in plastic Box with circuit printed on PCB with 2mm socket for test points & to see the waveforms 
• Set of Patch Chords & Experimental Manual. 

Frequency Shift Key Modulation And Demodulation Kit

• Built in Carrier Generator: 5 KHz, 1.85 KHz, 
• Built in Modulating Signal Generator 312, 156, 78 Hz 
• FSK Modulator 
• FSK Demodulator 
• Assembled in plastic Box with circuit printed on PCB with 2mm socket for test points & to see the waveforms 
• Set of Patch Chords & Experimental Manual. 
• Inbuilt power supply 

Phase Shift Key Modulation And Demodulation Kit

• Built in Carrier Generator: 10 KHz 
• Built in Modulating Signal Generator 1 KHz 
• PSK Modulator 
• PSK Demodulator 
• Assembled in plastic Box with circuit printed on PCB with 2mm socket for test points & to see the waveforms 
• Set of Patch Chords & Experimental Manual. 
• Inbuilt power supply

Delta Modulation/demodulation Kit

In Delta Modulation section the signal at time tn is compared with that at tn-1. 
The output is coded into a single bit (Delta Modulation output) which controls an 8 bit updown counter. 
The parallel output of the 8 bit counter is connected to an ADC which gives tn-1 amplitude level. 
The Delta Modulating output is connected to an 8 bit updown counter and a DAC followed by a low pass filter to regenerate the original analog signal. 
HARDWARE SPECIFICATION : 
Built in DC Power Supply 
Built in TTL Clock Generator 
Modulating signal Generator 1KHz with variable amplitude 
Delta Modulator 
Delta Demodulator 
Assembled in plastic Box with circuit printed on PCB with 2mm socket for test points & to see the waveforms 
Set of 2mm Patch Chords & Manual. 

TIME DIVISION MULTIPLEXING & DE-MULTIPLEXING KIT 

Built in DC Power Supply 
Data Generator 1 K b/s/Channel 
Low High ,Logic Low Sources 
Time Division Multiplexer 
LED indication for channel outputs 
Assembled in ABS plastic Box 
2mm socket for test points & to see the waveforms 
Set of Patch Chords & Experimental Manual. 

Salient Features:- 
On board sine generator (Sync) 
On board pulse generator 
4 Analog I/P channels sampled & Time Division Multiplexing 
5 Selectable sampling frequencies 
Selectable pulse duty cycle 
Selectable external/internal sampling 
4 channels de-multiplexer 
Generation of clock at Receiver by PLL system 
4th order butter worth low pass filters 
Technical Specifications:. 
Crystal Frequency : 6.4 MHz 
Analog Input Channel: 4 
Multiplexing: Time Division Multiplexing 
Modulation: Pulse Amplitude Modulation 
On board Analog Signal: 250Hz 500Hz 1 KHz & 2 KHz 
Sampling Rate: 16 KHz/ channel 
Sampling Pulse : With Duty Cycle variable from 0 – 19% in steps 
Clock Re-generation at Receiver: Using PLL 
Low Pass filter cut-off frequency : 3.4 KHz

Pulse Code Modulation/demodulation Trainer Kit

In the basic PCM Modulator the base band analog Signal is converted into 8 bit Digital format using an ADC. 
Sampling rate is set at 2.5 KHz. The 8 bit parallel data from ADC is converted into serial bit stream at 20 kbps. 
The PCM Demodulator receives the serial data, converts it into 8 bit parallel format. 
The Analog to Digital converter transforms the 8 bit parallel data into analog level. 
Thus the output of DAC is a stepped approximation of input signal. 
A low pass filter is used to recover the analog signal. 
HARDWARE SPECIFICATION : 
Inbuilt Power Supply 
Built in TTL Clock Generator 20 KHz 
Modulating signal Generator 100Hz to 5KHz 
PCM Encoder & PCM Decoder 
Data display with LED’s 
Assembled in plastic Box with circuit printed on PCB with 2mm socket for test points & to see the waveforms 
Set of 2mm Patch Chords & Manual. 

QUADRATURE PHASE SHIFT KEYING TRAINER 

Built in +/-5V/350 mA DC Power Supply 
Built in Carrier Generator 
Built in Modulating Signal Generator 
QPSK Modulator 
QPSK DEModulator 
Assembled in ABS plastic with circuit screen printed on Glass Epoxy PCB with 2mm socket for test points & to see the waveforms 
Set of Patch Chords & Experimental Manual. 

DSB/SSB AM TRANSMITTER TRAINER 

Technical Features: 
On board variable frequency audio oscillator, Carrier freq generator 
On board DSB & SSB Modulator, Band Pass filter, 455 KHz Generator, Audio & RF Amplifiers Transmitting Antenna, Speaker & Headphones 
Technical Specifications : * Audio Oscillator (Sine Wave Generator): 
Frequency : 300 Hz to 3.4 KHz * Amplitude : 0 to 2 Vp-p * Audio Input : Audio Pre-amplifier with microphone input. * Audio Input : Audio Pre-amplifier with microphone. 
Voltage Control Oscillator (VCO) : 
* Frequency Range : 1) 400 KHZ to 1500 KHz * Amplitude : 0 to 2 Vp-p * Output Impedance : 50 ohms 
AM/DSB/SSB/Modulator 
Modulation : Amplitude Modulation Double Side Band Single Side Band (USB & LSB) 
Carrier Input : 1 to 1000 KHz 
Modulating Input : 0.1 to 100 KHz 
Carrier Null : Adjustable 
Output Amplitude : Adjustable 
Ceramic Fileter 
Centre Frequency ; 455 KHz 
Band Width : 10 KHZ +/- 3 KHz 
Band Pass Filter : 
Central Frequency : 1.455 KHz 
Band Width : 10 KHz +/- 3 KHz 
Antenna : MW coil Antenna

Carrier Demodulation & Data (ask, Fsk, Psk & Qpsk  Demodulation) Re Formatting

It allow investigation of de- modulation of the transmitted modulated carrier and recovery of the original NRZ(L) data stream from the transmitted data representation 
Data Re-conditioning options : NRZ(L), NRZ(M), NRZ(S), RZ, AMI, Biphase (Manchester), Biphase (Mark), Biphase (Space) Carrier de-modulation techniques : ASK, FSK, PSK 
Receiver clock : Generated by phase-lock loop Interconnection : 2mm banana socket Power Supply : +5V, +/-12V 
LIST OF EXPERIMENT : 
• Data Decoding techniques for Non- Return to Zero format 
• Data Decoding techniques for phase encoded format 
• Data Decoding techniques for Return to Zero format and multilevel binary format 
Amplitude Shift Keying Demodulation Technique 
Frequancy Shift Keying Demodulation Technique 
Phase Shift Keying Demodulation Technique 
Quadrature Phase Shift Keying DeModulation Technique (QPSK) 

Transmission Line Trainer

Technical Specifications 
Transmission line: Co-axial cable 100m (25mx4) Impedance Matching 
Resistance:- 0-100W 2 nos. Test Generators:- 1. Sine Wave 4 KHz – 4MHz 2. Square Wave 40 KHz – 4 MHz * Interconnections: 4 mm banana socket 
Test Points: 10 
Power Supply: 220 Volt ±10%, 50Hz 
Power Consumption:- 3 VA approx. 
Accessories: Mains Cord, Set of Patch cord, Manuals, BNC – BNC cable, BNC – Crocodile clip, Multimedia interactive computer based training manual & software. 
Measurement with: (i) Matched (ii) Short (iii)Open end of the line 
(a) Measurement of line properties, Line attenuation, Freq characteristics of line, Input Impedance. (b) Measurement of stationery waves (c) Phase shift along the line (d) fault localization within the line (e) Line in pulsed condition. 

Pulse Code Modulation/transmitter Trainer

It has facility to generate the binary code of input signal, using analog to digital converter and time division multiplexing of two such PCM data stream. 
Input channels : 2 Nos. Time-division multiplexed, Pulse code modulated 
Onboard signals : 1KHz, 500 Hz variable amplitude synchronised sinewaves; Two variable amplitude DC levels 
Synchronization signal : Pseudo random code generation 
Parity code facility : Even, Odd, Hamming, No Parity 
Switch Fault mode : Facility to creat signal bit error using DIP switch 
LED Display : At every functional block for examination of Digital data and control signal 
Mode of Operation : Fast/Slow 
interconnectin :2mm banana socet 
in bulit power supply 
LIST OF EXPERIMENT : 
Study of 2 channel Time Division Multiplexing and its Pulse code modulation 
Study of Analog to Digital Principles 
study of pseudo Random sequences generatoin 
Study of error generation code logic using odd parity, even parity and hamming parity 
Study of effect to single bit error using switch faults. 

QUADRATURE PHASE SHIFT KEYING TRAINER 

Built in +/-5V/350 mA DC Power Supply 
Built in Carrier Generator 
Built in Modulating Signal Generator 
QPSK Modulator 
QPSK DEModulator 
Assembled in ABS plastic with circuit screen printed on Glass Epoxy PCB with 2mm socket for test points & to see the waveforms 
Set of Patch Chords & Experimental Manual. 

DSB/SSB AM TRANSMITTER TRAINER 

Technical Features: 
On board variable frequency audio oscillator, Carrier freq generator 
on board DSB & SSB Modulator , band pass filter ,455KHz Generator, Audio & RF Amplifiers Transmitting Antenna, Speaker & Headphones 
Technical Specifications : * Audio Oscillator (Sine Wave Generator): 
Frequency : 300 Hz to 3.4 KHz 
Amplitude : 0 to 2 Vp-p * Audio Input : Audio Pre-amplifier with microphone input. * Audio Input : Audio Pre-amplifier with microphone. 
Voltage Control Oscillator (VCO) : 
Output Signal : Sine Wave 

Salient Features * On board variable capacitor training * On board receiving antenna, Local Oscillator, BFO, RF Amplifier, Mixer, IF Amplifiers, Detectors, AGC, Audio o/p amplifier, Speaker & Headphones 
Super heterodyne Receiver 
Frequency range: 400KHz to 1.5 MHz 
Intermediate Frequency: 455 KHz 
Inputs: RF Signal 
Output: IF frequency 455 KHz adjustable 
F1 filter: Duel Tune LC RF Amplifier with variable gain: Mixer(Frequency converter) 
Dual Gate MOSFET 
nput : Local Oscillator & RF 
Output frequency: 455 KHz adjustable F1 Filter : Duel Tune LC Local Oscillator 
Output signal : Sine wave for local Osc. Input 
Frequency: From 900KHz to 2.2 MHz gang tuned 
Amplitude: adjustable from 0 – 2 V p-p 
Output Impedance: 50 Ohms 
1st IF & IInd IF Amplifier: 
Central frequency: 455 KHz 
Load Impedance: Variable R-L-C 
Gain; Automatic Gain Control 
Gain 1 – 43 dB and * Gain 2 – 47 Db 
Diode Envelope Detector: * Detection of the positive and negative envelope with variable R-C filter DSB Product Detector: * Operating frequency: Adjustable from 400KHz to 500KHz SSB Input Amplitude: 1 Volt p-p

Carrier modulation & data formatting trainer (ask, fsk, psk & qpsk - modulation) 

It allow to study the conversion of non-return-to-zero (nrz) waveform to six different data formats and study the modulation techniques such as ask, fsk, psk 
data conditioning options : nrz(l), nrz(m), nrz(s), rz, ami, biphase (manchester), biphase (mark), 
biphase (space) carrier modulation techniques : ask, fsk, psk on-board carrier signal : 2mhz sinewave, 1mhz sinewave 1mhz cosinewave 
Interconnection : 2mm banana socket power supply : +5v, +/-12v list of experiment : 
data coding techniques for non-return to zero format 
data coding techniques for phase encoded format 
data coding techniques for return to zero format and multilevel binary format 
amplitude shift keying modulation technique (ask) 
frequancy shift keying modulation technique (fsk) 
phase shift keying modulation technique (psk) 
quadrature phase shift keying modulation technique (qpsk) 

Delta, Adaptive Delta & Delta Sigma Modulation & And Demodulation Trainer

The kit provides facility to examine Delta & Adaptive Modulation and Demodulation. 
An exhaustive manual is provided with the system, which provides detailed experimental procedure and complete circuit diagram of the system 
Delta Modulation Techniques : Delta Modulation/Demodulation Adaptive Delta Modulation/Demodulation 
Onboard sampling frequency : 8KHz, 16KHz, 32KHz, 64KHz 
Onboard sine wave generator : 250Hz, 500Hz, 1KHz, 2KHz and DC level (variable Amplitude 0-5 V p-p) 
Low pass filter type : 2nd & 4th order butter worth filter 
Cut-off frequency : 3.4 KHz 
Interconnection : Banana Post 
Power Supply : +5V, +/-12V, 1Amp. 
LIST OF EXPERIMENT : 
Study of Delta Modulation & Demodulation 
Study of effect of slope overload and increased integrator gain in Delta Modulation 
Study of Adaptive Delta Modulation & Demodulation 
Study of Delta Sigma Modulation & Demodulation 
Study of Compander and expander 
Study of voice communication 

Pam-pwm-ppm Modulation & Demodulation Trainer Kit

Pulse Modulation Techniques: 
Pulse Amplitude Modulation 
Pulse Width Modulation 
Pulse Position Modulation 
On-board Sampling Frequencies (Pulse):- 8KHz, 16KHz, 32KHz, 64KHz 
On-board Generator:- 1.Sine Wave:- 1KHz & 2KHz (Gain adjustable) 2.Square wave:- 1KHz & 2KHz (optional) 
Low Pass Filter: 4m order VW Filter 
Voice Communication: Voice link using dynamic mic & speaker AC Amplifier with adjustable gain control DC Out put: -4 V(variable) 
Switched faults : 8 nos. 
Interconnections:- 4mm banana sockets 
Test Points: 29 
Power Supply: 220V ±10%, 50Hz 
Included:- Manual , Set of Patch cords, Line Cord, Microphone, Head Phone 
Experiments : 
PAM using natural & flat top sampling 
Samples, Sample & Hold & Flat top out puts in PAM. 
PPM using DC & AC (Sine Wave) Modulating Signals. 
Pulse Position Demodulation 
Pulse width Modulation &Demodulation 

Analog Signal Sampling & Reconstruction Trainer

Crystal controlled Pulse Generator 
Demonstrates Sampling and Reconstruction 
On board Analog Generator 
Selectable Sampling Frequencies 
Sampling Pulse Duty cycle selectable 
Internal/external sampling input selectable 
Separate Sample and Sample/Hold outputs. 
On-board 2nd order and 4th order L.P. Filters. 
Crystal frequency: 6.4 MHz 
Sampling frequency:2, 4, 8, 16 & 32 KHz (switch selectable) 
On board Generator: Synchronized 1 KHz sine wave (5 Vp-p) 
Duty Cycle: 0.90% in Decade steps (switch selectable) 
L.P. Filters : Butter worth 2nd & 4th order filter cut off frequency 3.4 KHz 
Inbuilt Power Supply 
Assembled in ABS plastic cabinet with cover 
Set of Patch Chords & Experimental Manual. 

Fdm Modulation/ Demodulation Trainer

Technical Specifications: 
Channel : Two channel FDM with One channel audio 
Carrier Generators: Two Carrier Generators 
Modulation Input Frequencies: Two separate Sine Waves (a) 1 KHz (b) 10KHz (of variable Freq. & variable amplitude). Modulators: Two DSBSC 
Demodulators: Two DSBSC modulators 
Filters: Two separate fourth order low pass butter worth Filter with Cut off freq of 10KHz 
Test Points :- 46 nos. 
Interconnections: 2/4mm Banana socket 
Power Requirement:- 230 +10%, 50Hz AC 
Accessories :- Detailed Instruction Manual, One Micro phone, One Head phone, Set of 12 patch cards, Multimedia interactive computer based training manual & software. 
Experiments :- 
Two Channel FDM with one channel as audio. 
Study & demonstrate the carrier generation, AM, DSBSC Modulation. 
Study DSBSC demodulation. 

Qam Trainer Kit

Data Generator : Onboard 24 data bit generator 
Phase Generator : onboard 4 phase generator 
Encoder & Decoder : Onboard Tri-Bit Encoder-Decoder 
Data Switches : Onboard DIP switches for I, C, Q 
World clock : Onboard world clock generator to show the start of 24 bit data word 
Input Display Buffer : Onboard 24 bit data display with the help Of tricolour LED’s More than 35 test points for intermediate signal display 
Fault switches : 16 fault simulated switches 
Data Speed : Fixed generator than 4.5 KHz 
Data Format : Synchronous with carrier 
D Sequence : 24 bit user selectable data with the help of 3x8 Dip switches 
Sine & Cosine Carrier Generator 4.5 KHz (approx.) 
Inbuilt power supply 
Assembled in ABS plastic box with cover 
Set of patch chords & users manual 

Digital Communication Trainer (ask, Fsk, Psk & Qpsk Modulation/Demodulation)

Specifications:
It demonstrate ASK, FSK, PSK and it’s variation like QPSK Carrier Modulation and Demodulation techniques. 
Inbuilt Power Supply. 
On-Board synchronized Source. 
Various test points provided on-board with comprehensive instruction manual. 
Inbuilt power supply 
Assembled in ABS plastic box with cover 
Set of patch chords & users manual 

Analog Communication Trainer (am, Fm & Pm Modulation/ Demodulation)

Specifications:
It demonstrate AM, FM & PM (Phase Modulation) Modulation and Demodulation techniques.. 
On-Board synchronized Source. 
Various test points provided on-board with comprehensive instruction manual. 
Inbuilt power supply 
Assembled in ABS plastic box with cover 
Set of patch chords & users manual 
Trainer demonstrates the principle of Amplitude Mod. & Demod. 
Built - in IC based DC regulated power supply 
On-Board Audio Oscillator 100Hz to 10KHz. 
Amplitude Modulation. Double Sideband AM Generation. Single Sideband AM Generation (USB/ LSB). 
O/P Amplifier Audio Pre-Amplifier. Ceramic Filter. & On- Board Antenna. 
It would also demonstrate Frequency Modulation & Demodulation and also demonstrate Phase Modulation and Demodulation 
FM Modulator: 1.Varactor Modulator, 2.FMvia PM. PM Modulator. 

Superhetrodyne Radio Receiver Trainer

Used for AM reception. 
Fault creation to understand block of super hetrodyne reception. 
Circuit diagram display on the PCB. 
Self contained unit to understand and demonstrate principle of super hetrodyne receiver. 
Characteristics & alingnment features. 
Adjustment and control at all stages 
Signal level meter supplied alongwith the equipment. 
Power : 230V, +/-10%, 50Hz 
Accessories : User’s Manual with Experimental book and patch cords.