40708 is versatile trainer which is suitable to conduct both Analog and Digital Communication experiments. This Board consists of Master base unit in which has all sources like Sine generator, Low pass amplifiers, Speaker, MIC, Data, Clock, Selectable Pulse generator, Variable DC supply etc. Various Plug in Modules are provided as per the experiments for studying Analog & Digital communication.

Specification:
1.    Fixed Sine Wave Generator

• Provides fixed Sine waveform Natural & Flat Top output of 250Hz, 500Hz, 1 KHz, and 2 KHz. 
• Amplitude adjustments of 0 - 4Vp-p 

2.    Variable Sine Wave Generator

• Provides Sine waveform output from 1Hz to 10KHz
• Provision for Amplitude adjustments provided for 10Vp-p 

3.    DC Source

• One No. of variable (0-5V) DC source.
• Provision for Amplitude adjustments provided

4.    Pulse Generator

• Switch selectable sampling clock of 2, 4, 8, 16, 32, 64 KHz.
• Crystal Controlled Pulse Generator
• Switch selectable Duty cycle of 10-90% in steps of 10%.

5.    Clock and Data Generator

• 8 bit variable NRZ-L pattern generated of 8-dit Data Switch provided.
• Clock Frequency is of 250 KHz.
• 8KHz frame frequency

6.    PRBS Generator

• Fast (240 KHz/Channel approx)
• Slow (1Hz. /channel approx.)

7.    Carrier Sine Wave Generator

• Provides synchronized Sine output of 500KHz(0 deg.), 500KHz(90 deg.), 500KHz(180 deg.), 500KHz(270 deg.),
• 1MHz(0 deg.) & 1MHz(180 deg.).

8.    On-board features

• MIC & Speaker interface circuit for Voice Link
• 1 no. of 2nd order Low pass filter with cut off frequency of 3.4 KHz.
• 5 no’s of 4th order Butterworth Low pass filter with cut off frequency of 3.4 KHz.
• 26 Pin FRC male Connector provided for interfacing Experimental Module
• Block Description Screen printed on glassy epoxy PCB
• All interconnections are made using 2mm banana Patch cords
• Test points are provided to analyze signals at various points.
• Bare board Tested Glass Epoxy SMOBC PCB is used.
• In-Built Power Supply of +5V/1.5A, ±12V/250mA with Power ON indication
• Space provided to place ready to use analog/digital communication module
• Attractive Metal Enclosure for base unit.

List of Optional Modules

1.  DSB/SSB AM Modulation & Demodulation: Order Code - 40708-M01     Qty.01 
2. FM Modulation & Demodulation Module: Order Code - 40708-M02     Qty.01
3. Fibre Optics Module: Order Code - 40708-M03     Qty.01
4. PAM/PWM/PPM/TDM Module: Order Code - 40708-M04     Qty.01
5. TDM Pulse Code Modulation & Demodulation Module: Order Code - 40708-M05     Qty.01
6. Line Coding & Decoding Module: Order Code - 40708-M06     Qty.01
7. ASK/FSK/PSK/QPSK Module: Order Code - 40708-M07    Qty.01 
8. Delta Modulator & Demodulator Module: Order Code - 40708-M08    Qty.01

Order Code - 40708-M01 
DSB/SSB AM Modulation & Demodulation Module
Need Communication System Trainer Master Unit for performing the Experimental module

1. On-board features
   1. 2 Nos. of Balanced Modulator with band pass filter (1MHz) & 1 No. of balanced modulator (455KHz)
   2. Ceramic band pass filter
   3. Carrier Frequency of 1MHz
   4. Frequency range of 525 to 1625Khz.
   5. Receiver CKT consist of RF Amplifier, Mixer, Local Oscillator, BFO, IF amplifier-1, IF amplifier-2.
   6. Diode detector for DSB & Product detector for SSB.
   7. Block Description Screen printed on glassy epoxy PCB

Order Code - 40708-M02
FM Modulation & Demodulation Module
Need Communication System Trainer
Master Unit for performing the Experimental module

1. On-board features
   1. FM Modulation using Reactance Modulator & Varactor Modulator.
   2. Transmitter Frequency to 455 KHz.
   3. FM Demodulator using Detuned Resonant detector, Quadrature detector, Foster Seeley detector, Ratio detector & PLL detector
   4. Block Description Screen printed on glassy epoxy PCB

Order Code - 40708-M03
Fibre Optics Module
Need Communication System Trainer
Master Unit for performing the Experimental module

1. On-board features
   1. Transmitter One Fiber Optics LED having peak wavelength of emission 660 nm. & One Fiber Optics LED having peak wavelength of emission 850 nm
   2. Receiver one Analog & One Digital Fiber Optic photo detector
   3. Drivers Analog & Digital
   4. Analog Band Width 100Mbd. & Digital Band Width 5mbit/sec
   5. Block Description Screen printed on glassy epoxy PCB
   6. On board Analog & Digital Buffer with Filter Amplifier
2. Fibre Cable
   1. Cable Type Step indexed multimode PMMA plastic cable
   2. Core Refractive Index 1.492 & Clad Refractive Index 1.406
   3. Numerical aperture Better than 0.5
   4. Acceptance Angle Better than 60o
   5. Fiber Diameter 1000 microns
   6. Outer Diameter 2.2mm
   7. Fiber Length 1Meter & 1/2Meter

Order Code - 40708-M04
PAM/PWM/PPM/TDM Module
Need Universal Communication System Trainer Master Unit for performing the Experimental module

1. On-board features
   1. Analog Sample Circuit Out put
   2. Sample & Hold Circuit Out put
   3. Sampling rate of 32 KHz/channel for TDM PAM
   4. 8KHz. Channel Identification Signal for TDM PAM
   5. Four Analog Input Channels for TDM PAM Multiplexing/De-multiplexing
   6. Block Description Screen printed on glassy epoxy PCB
   7. Modulation Techniques
   8. PAM modulation & demodulation
   9. PWM modulation & demodulation
   10. PPM modulation & demodulation
   11. TDM-PAM modulation & demodulation

Order Code - 40708-M05
TDM Pulse Code Modulation And De-modulation Module
Need Universal Communication System Trainer Master Unit for performing the Experimental module

1. On-board features
   1. Two Nos. of Input Channels.
   2. 2 Channel Time Division Multiplexed Pulse Code Modulation Receiver.
   3. Error Detection of None, Even, Odd, Hamming
   4. Error Correction using Hamming Code technique
   5. None, Even, Odd, Hamming Parity selections
   6. Four Switched Faults for Fault Selection
   7. Block Description Screen printed on glassy epoxy PCB
   8. Modulation Techniques
   9. TDM Pulse Code modulation
   10. TDM Pulse Code demodulation

Order Code - 40708-M06
Line Coding & Decoding Module
Need Universal Communication
System Trainer Master Unit for performing the Experimental module

1. Data Format (Coding & decoding)
   1. - NRZ (Level), NRZ (Mark), NRZ (Space), Bi-phase (Manchester), Biphase (Mark), Bi-phase (Space), URZ, AMI.
2. On board features
   1. Uni-polar to Bipolar conversion
   2. Bipolar to Uni-polar conversion.
   3. Block Description Screen printed on glassy epoxy PCB

Order Code - 40708-M07
ASK/FSK/PSK/QPSK Module
Need Universal Communication System Trainer Master Unit for performing the Experimental module

1. Carrier Modulation Techniques
   1. ASK modulation
   2. FSK modulation
   3. PSK modulation
   4. QPSK Modulation
2. Data Format (Coding)
   1. Dibit Pair I & Q Bits.
   2. Carrier Demodulation Techniques
   3. ASK Demodulation
   4. FSK Demodulation
   5. PSK Demodulation
   6. QPSK Demodulation
3. On board features
   1. Phase Reset Switch is provided for QPSK Demodulation.
   2. Block Description Screen printed on glassy epoxy PCB 

Order Code - 40708-M08
Delta Modulator & Demodulator Module
Need Universal Communication System Trainer Master Unit for performing the Experimental module

1. Modulation Techniques
   1. Delta modulation
   2. CVSD modulation
2. Demodulation Techniques
   1. Delta Demodulation
   2. CVSD Demodulation
3. On board features
   1. M-law Compander and Expander
   2. Block Description Screen printed on glassy epoxy PCB