ABSTRACT
Pseudo random binary sequence is essentially a random sequence of binary numbers. So PRBS
generator is nothing but random binary number generator. It is ‘random’ in a sense that the value
of an element of the sequence is independent of the values of any of the other elements. It is
'pseudo' because it is deterministic and after N elements it starts to repeat itself, unlike real
random sequences. The implementation of PRBS generator is based on the linear feedback shift
register (LFSR). The PRBS generator produces a predefined sequence of 1's and 0's. Sequences
of consecutive bits comprise one data pattern, and this pattern will repeat itself over time. The
primary goal of the project is to generate a predefined sequence of 3 bit random numbers using a
pseudo random sequence generator. The next step involves comparing the generated random
sequence with a given sequence, and if the sequences are matched, then the corresponding
appliance can be activated. The entire design of the PRBS generator was implemented using
hardware components – ICs’ and Digital IC Trainer Kit. We have used three D Flip-Flops for
generating the pseudo random sequence. The outputs of the second and third flip-flops were
XORed together and fed as feedback to the first flip-flop. The output of the PRBS generator
cycles between 0 and 7. This generated sequence was fed as one of the inputs to the Equality
Detector, whose other input was characteristic of the appliance and supplied via the IC trainer
kit. We used an LED in place of an appliance. When the generated pseudo random sequence
matched with the input sequence, the LED would glow.
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TABLE OF CONTENTS
CHAPTER NO
1
2
TITLE
PAGE NO
ABSTRACT
i
TABLE OF CONTENTS
ii
LIST OF FIGURES
iv
LIST OF TABLES
v
LIST OF ABBREVIATIONS
vi
ACTIVATION OF REMOTE DEVICES
1
1.1 Introduction
1
1.2 Device Activation
1
PSEUDO RANDOM SEQUENCE
GENERATOR
2
2.1 Introduction
2
2.2 Linear Feedback Shift Register
3
2.2.1 Introduction
3
2.2.2 Feedback Action
5
2.2.3 Tapping Action
5
2.3 Properties of PRBS
3
6
GENERATION OF PSEUDO RANDOM
7
SEQUENCE
3.1 Introduction
7
3.2 IC 7474
7
3.2.1 Introduction
7
3.2.2 Pin Configuration
8
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CHAPTER NO
TITLE
PAGE NO
3.3 IC 7486
4
9
3.3.1 Introduction
9
3.3.2 Pin Configuration
10
HARDWARE IMPLEMENTATION
11
4.1 Circuit Diagram of PRBS
11
4.2 Equality Detector(IC 74 HC688)
12
4.2.1 Introduction
12
4.2.2 Pin Configuration
13
4.3 Block Diagram for comparison
14
5
SNAPSHOT
15
6
CONCLUSION
16
REFERENCES
17
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LIST OF FIGURES
FIGURE NO
TITLE
PAGE NO
2.1
Illustration of Pseudo Random Number Cycle
2
2.2
A 3 Bit Shift Register
3
3.1
Pin Diagram of IC 7474
7
3.2
Pin Diagram of IC 7486
9
4.1
Circuit Diagram of PRBS
11
4.2
Pin Diagram of IC 74HC688
12
4.3
Block diagram for comparison
14
iv
LIST OF TABLES
TABLE NO
TITLE
PAGE NO
3.1
Pin Configuration of IC 7474
8
3.2
Truth Table for IC 7486
9
3.3
Pin configuration of IC 7486.
10
4.1
Pin Configuration of IC 74HC688
13
4.2
Truth Table for IC 74HC688
13
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LIST OF ABBREVIATIONS
ABBREVIATION
EXPANSION
PRBS
Pseudo Random Binary Sequence
LFSR
Linear Feedback Shift Register
EX-OR
Exclusive OR
LED
Light Emitting Diode
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