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Advanced communication modules from M/s Yellow Fourier Technologies (a company incubated at IITG) has been used.

 

1. TTL _Level Oscillator Module 2. High Frequency Prescaler Module. 3. Pseudo Random Data Generator Module. 4.10.7MHz BPSK/ASK Transmitter Trainer Kit.                                                                        5. TX Channel Isolation Board. 6. RX Channel Isolation Board 7. 10.495 MHz Add-on Oscillator 8. 10.7 MHz BPSK/ASK Receiver Trainer Kit. 9. Agilent 54622D oscilloscope

NI LabVIEW 2009 has been used for instrument control as well as for web interface.

 

TTL Level Oscillator Module

BPSK Experiment Set up

 

TTL-Level Oscillator Module

The crystal oscillator module contains a combination of accurate crystal oscillator boards, which completely generate all the frequencies required at the transmitter end of the communication system. The amplitude level of the output for each of these boards is 0-5 Volt square wave (TTL-level). The output frequency for these individual boards can be:

2.70000 MHz
8.00000 MHz
10.00000 MHz
10.49500 MHz

High Frequency Prescaler Module

 

High Frequency Prescaler Module

The Prescaler Module is primarily intended to prescale or divide high input frequencies, to generate lower-frequency data rate clocks. It is equipped with zero-loading protection.

Two sections are provided on the Prescaler Module. Section 1 and Scetion 2 provide a different choice of frequency division factors. Section 1 is also used in our typical communication system setup, and generates 8 data rates depending on choice of the three Select signal S0, S1 and S2. Typical data rates like 0.5, 1, 2, 4, 8, 16, 32, 64 and 128 kbps can be generated here, by combining this module with the appropriate board in the crystal oscillator module. Section 2 provides different division/ prescaling factors and thus offers the flexibility to be used for experimental purposes and for integration in any other system that the students/faculty/developers might be conceiving in a lab setup.

Technical Specifications of High frequency Prescaler Module

Prescaler 1:

Clock input =5V TTL-Level; Clock Output=5V TTL-Level

Dividing factor Selector: Jumper Settings- S2,S1,S0

S2	S1	S0	Clock Input	Clock Output
0	0	0	f	f/5120
0	0	1	f	f/2560
0	1	0	f	f/1280
0	1	1	f	f/640
1	0	0	f	f/320
1	0	1	f	f/160
1	1	0	f	f/80
1	1	1	f	f/40

Prescaler 2:

Clock input =5V TTL-Level; Clock Output=5V TTL-Level

Dividing factor Selector: Jumper Settings- S2,S1,S0

S2	S1	S0	Clock Input	Clock Output
0	0	0	f	f/100
0	0	1	f	f/20
0	1	0	f	f/16
0	1	1	f	f/10
1	0	0	f	f/8
1	0	1	f	f/5
1	1	0	f	f/4
1	1	1	f	f/2

Pseudo Random Data generator Module

 

The PRBS (Pseudo Random Binary Sequence) Module

It is used to generate seemingly random sequences at a given data rate clock. The purpose of this module is to nearly emulate conditions of real time data. Two options are provided onboard for the sequence length via a jumper:

Short Sequence

This a Modulo-4 PRBS sequence. Modulo-4 implies a 15 bit long random sequence, i.e. (2^[4] - 1). The reason for putting an option of a short sequence in PRBS generation, is for the ease of comparitively observing demodulated data versus transmitted data.

Long Sequence

This a Modulo-15 PRBS sequence. Modulo-15 implies a 32,767 bit long random sequence, i.e. (2^[15] - 1). The reason for putting an option of a long sequence in PRBS generation, is to emulate conditions of randomness in real-time data, and showcase this feature to the students during experimentation.

Modulation and TX Channel Isolation Module

 

Transmitter(Tx) Channel Isolation Module

The purpose of the Transmitter Channel isolation board is to provide inductive isolation between the communication transmitter and a communication receiver. This enables ground isolation, thus emulating real-time conditions.

The Upconverter Module provides facility to upconvert an incoming carrier or modulated waveform (Frequency F_c) by the upconverting Local Oscillator (Frequency F_lo). Thus the primary output frequency of the upconverter is centered around F_c + F_lo. This upconverter is digital in nature, and is provided with a filter at the output, which works at F_c + F_lo = 10.7 MHz. Also, for ease of operation, and reduction in required lab space, we have recently integrated our Upconverter Module with each of the available Modulator Modules.

 

Receiver(Rx) Channel Isolation Module

The purpose of the Receiver Channel isolation board is to provide inductive isolation between the communication transmitter and a communication receiver. This enables ground isolation, thus emulating real-time conditions. Also, the receiver and the transmitter channel isolation Modules are designed to be matched for optimum functioning of the link.

Local Oscillator Module

The Downconverting Local Oscillator Module comprises of an accurate 10.49500 MHz crystal generating a low-amplitude sinusoidal signal, to be fed to the analog downconverter.

 

BPSK Squaring loop Demodulator Module

Squaring Loop BPSK Demodulator Module

The Squaring Loop BPSK Demodulator Module, can demodulate a direct BPSK signal or demodulate a downconverted high frequency BPSK modulated signal. Demodulation typically occurs well, till 64kbps data rate, at a downconverted or direct modulated frequency around 200 kHz. A Downconverter Module has also been integrated onboard for higher flexibility. The Squaring Loop lock range is typically around 20kHz.

The availability of two different demodulator modules (i.e. Costas Loop and Squaring Loop) for BPSK, enables the student to perform a comparitive analysis through experimentation and observation. Our Eye Diagram Analysis Module can also be used for this purpose.

BPSK Costas loop Demodulator Module

Costas Loop BPSK Demodulator Module

The Costas Loop BPSK Demodulator Module, can demodulate a direct BPSK signal or demodulate a downconverted high frequency BPSK modulated signal. This Module has been exclusively designed at Yellow Fourier to achieve a low-cost discrete hardware implementation, and is currently under the patent filing process.

Costas Loop Demodulator Module typically occurs well, till 64kbps data rate, at a downconverted or direct modulated frequency around 200 kHz. A Downconverter Module has also been integrated onboard for higher flexibility. The Costas Loop lock range is typically around 20kHz.

Power Supply Module

 

Power Supply Module

This Module comprises of a Power supply SMPS unit and a smart card set for easy distribution of power to the individual modules at the transmitter and the receiver end respectively.