DIGITAL COMMUNICATIONS
LAB MANUAL
(STUDENT COPY)
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
GUDLAVALLERU ENGINEERING COLLEGE
SESHADRI RAO KNOWLEDGE VILLAGE::GUDLAVALLERU
INDEX
S.NO.
NAME OF THE EXPERIMENT
PAGE NO.
1
Time Division Multiplexing
1-4
2
Pulse Code Modulation & Demodulation
5-8
3
Differential Pulse Code Modulation & Demodulation
9-12
4
Delta Modulation
13-16
5
Frequency Shift Keying
17-19
6
Phase Shift Keying
20-22
7
Differential phase shift keying
23-26
8
Companding
27-35
9
Linear Block Code- Encoder and Decoder
36-39
10
Binary Cyclic Code- Encoder and Decoder
40-42
ADDITIONAL EXPERIMENTS
1
Amplitude Shift Keying
43-45
2
Time Division Multiplexing & De multiplexing (Digital)
46-48
3
MATLAB Program for ASK Modulation & Demodulation
49-51
4
MATLAB Program for PSK Modulation & Demodulation
52-55
5
MATLAB Program for FSK Modulation & Demodulation
56-59
6
MATLAB Program for QPSK Modulation & Demodulation
60-66
APPENDIX
REFERENCES
67-72
73
Digital Communication Lab
Additional Experiments
APPENDIX
ELECTRONICS & COMMUNICATION ENGINEERING
1. TIME DIVISION MULTIPLEXING AND
DEMULTIPLEXING
Aim:
1. To study the 4 channel analog multiplexing and demultiplexing
2. To study the effect of sampling frequency on output signal
characteristics.
3.
To study the effect of input signal amplitude on the output signal
characteristics.
Apparatus required:
1. Time Division Multiplexing and de multiplexing trainer Kit.
2. Dual Trace oscilloscope
Theory:
In PAM, PPM the pulse is present for a short duration and for most of the time
between the two pulses no signal is present. This free space between the pulses
can be occupied by pulses from other channels. This is known as Time Division
Multiplexing. Thus, time division multiplexing makes maximum utilization of the
transmission channel. Each channel to be transmitted is passed through the low
pass filter. The outputs of the low pass filters are connected to the rotating
sampling switch (or) commutator. It takes the sample from each channel per
revolution and rotates at the rate of f s. Thus the sampling frequency becomes fs
the single signal composed due to multiplexing of input channels. These
channels signals are then passed through low pass reconstruction filters. If the
highest signal frequency present in all the channels is f m, then by sampling
theorem, the sampling frequency f s must be such that fs≥2fm. Therefore, the time
space between successive samples from any one input will be Ts=1/fs , and
Ts ≤ 1/2fm.
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Circuit Diagram:
Fig: 1 Time Division Multiplexing And Demultiplexing Circuit
Procedure:
There are 4 signal sources;
a) AF Signal generator
b) Triangular wave generator
c) Square wave generator and
d) Sine wave generator
1. Connect these four signals to four inputs of the Multiplexer. Adjust each signal
amplitude to be with in +/-2V (p-p) and frequency non-over lapping within a
frequency band of 300Hz.
2. Connect A, B output of 7476 to A1, B l inputs of Multiplexer.
3. Adjust the frequency of IC 8038 (Square wave, triangular wave generator) to
be around 32 KHz, so that each of the Four channels are sampled at 8 KHz.
4. Adjust the pulse width of 555 timers to be around 10µsecs.
5. Observe the 4 output pin 11 of 7476 on one channel 1and TDM output pin 13
of CD4052 on second channel of oscilloscope. Synchronize scope Internal-CH
1 mode. All the multiplexed channels are observed during the full period of the
clock (1/32 KHz).
6. Connect TDM output to comparator –ve input and saw tooth wave to +ve
Input. Observe the Comparator output. The PAM pulses are now converted in
to PWM pulses.
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7. Connect the PWM pulses to TDM input of De multiplexer at pin 3 of second
CD4052. Observe the individual outputs Y0, Y1, Y2, and Y3 at pin 1, 5, 2 & 4
of CD4052 respectively. The PWM pulses corresponding to each channels
are now separated as 4 streams.
8. Take one output and connect it to Low Pass Filter and the Low Pass Filter
output to Amplifier. Observe the output of the amplifier in conjunction with the
corresponding input. Repeat this for all 4 inputs. This is the Demodulated
TDM output. Any slight variation in frequency, amplitude is reflected in the
corresponding output.
Observations:
Input Signal
S.No
Type of Signal
1
AF signal
2
Sine wave
3
Square wave
4
Triangular wave
Amplitude
Time period
(Vp-p)
(ms)
Multiplexed output
Time
No. of
Slot(ms)
cycles
Model Waveform:
Multiplexed Output Waveform
Inference:
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Questions:
1. What is TDM?
2. Applications of TDM?
3. What is the effect of amplitude and frequency of input signals on
output?
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2. PULSE CODE MODULATION AND
DE MODULATION
Aim:
To obtain the pulse code modulation and de modulation signals.
Apparatus required:
1. PCM trainer kit
2. Dual Trace Oscilloscope.
Theory:
Pulse Code Modulation is known as digital pulse modulation technique. In fact,
the pulse code modulation technique that the message signal is subjected to a
great number of operations. It consists of 3 main parts i.e., transmitter,
transmission path and receiver. The essential operations in the transmitter of a
PCM system are sampling, quantizing and encoding. Sampling is the operation in
which an analog signal is sampled according to the sampling theorem resulting in
a discrete time signal. The quantizing and encoding operations are usually
performed in the same circuit which is known as an ADC. Also, the essential
operations in the receiver are regeneration of impaired signals, decoding and
demodulation of the train of quantized samples. These operations are usually
performed in the same circuit which is known as digital to analog converter.
Further at intermediate points along the transmission route from the transmitter to
the receiver, regenerative repeaters are used to reconstruct the transmitted
sequence of coded pulses in order to combat the accumulated effects of signal
distortion and noise. The quantization refers to the use of a finite set of amplitude
levels and the selection of a level nearest to a particular sample value of the
message signal as the representation the system at transmission in which
sampled and quantized values of an analog signal are transmitted via a
sequence of code words is called Pulse Code Modulation. Two most commonly
used versions are the differential pulse code modulation and delta modulation.
The PCM communication system is shown in Fig1. In the circuit is often called an
analog to digital converter. The functional block that performs the task of
accepting binary digits and generating appropriate sequences of levels is called a
digital to analog converter. The bandwidth of PCM will be much greater than that
of the message. PCM is used to convert analog signals to binary form. Low pass
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filter may be used to reduce the quantization noise and it yields the original
message signal.
Circuit Diagram:
Fig: 1 Pulse Code Modulation and Demodulation Circuit
Procedure:
1. Make the connections as per the diagram as shown in the Fig.1.and
switch on the power supply of the trainer kit.
2. Clock generator generates a 20 KHz clock .This can be given as
input to the timing and control circuit and observe the sampling
frequency fs= 2 KHz approximately at the output of timing and control
circuit.
3. Apply the signal generator output of 6V(p-p) approximately to the A to
D converter input and note down the binary word from LED’s i.e. LED
“ON” represents ‘1’ & “OFF” represents ‘0’
4. Feed the PCM waveform to the demodulator circuit and observe the
waveform at the output of D/A which is quantized level.
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Model Waveforms:
(a)
(b)
(c)
Fig: 2 Waveforms of (a) Modulating Signal (b) Sampling Signal (c) PCM output
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Apply the DC control voltage
Bit sequence
DC voltage(v)
MSB
LSB
-4
-3
-2
4
5
Questions:
1. What is the need of parallel to serial converter?
2. What is the use of Companding?
3.
What are the applications of PCM?
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3. DIFFERENTIAL PULSE CODE MODULATION AND
DEMODULATION
Aim:
To study the differential PCM & demodulation by sending variable
frequency sine wave & variable DC signal input.
Apparatus required:
1. AF oscillator
2. DPCM modulator
3. DPCM demodulator
4. Connecting wires
5. CRO - 30MHz
6. Variable DC Source – 1
Theory:
In this DPCM instead of transmitting a base band signal m(t) we send the
difference signal of Kth sample and (k-1) th sample value. The advantage here is
fewer levels are required to quantize the difference than the required to quantize
m(t) and correspondingly, fewer bits will be needed to encode the levels. If we
know the post behaviour of a signal up to a certain time, it is possible to make
some interference about its future values this is called prediction. The filter
designed to perform the prediction is called a predictor. The difference between
the interest and the predictor o/p is called the prediction error.
Circuit Diagram:
Fig:1 Differential Pulse Code Modulation Circuit
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Fig: 2 Differential Pulse Code Demodulation Circuit
Procedure:
1. Switch on the experimental kit.
2. Apply the variable DC signal of amplitude 6v(p-p) with frequency of 80Hz
to the input terminals of DPCM modulator.
3. Observe the sampling signal of amplitude 5v (p-p) with frequency 20KHz
on channel 1 of a CRO.
4. Observe the output of DPCM on the second channel.
5. By adjusting the DC voltage potentiometer, observe the DPCM output.
6. During the demodulation connect DPCM output to the input of
demodulator and observe the output of DPCM demodulator.
Model waveforms:
(a)
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(b)
(c)
Fig: 3 Waveforms of (a) Sampling Signal (b) Modulating Signal (c) DPCM Output
(a)
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(b)
Fig. 4 Output of (a) D/A Converter (b) Demodulated
Inference:
Questions:
1. What is the effect sampling signal?
2. Write the advantage of DPCM compared with PCM?
3. What is the one bit version of DPCM?
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4. DELTA MODULATION
Aim:
To obtain the delta modulation and demodulation signals.
Apparatus required:
1. Delta Modulation & Demodulation Kit
2. Cathode Ray Oscilloscope 0-30MHz
Theory:
Delta modulation uses a single bit PCM code to achieve digital transmission of
analog signals with conventional PCM each code is binary representation of both
the sign and magnitude of a particular sample. With delta modulation, rather than
transmit a coded representation of the sample, only a single bit is transmitted,
which indicates whether that sample is larger or smaller than the previous
sample. The algorithm for a delta modulation system is quite simple. If the
current sample is smaller than the previous sample, a logic 0 is transmitted. If the
current sample is larger than the previous sample, a logic 1 is transmitted. The
input analog is sampled and converted to a PAM signal, which is compared to
the output of the DAC. The output of the DAC is a voltage equal to the
regenerated magnitude of the previous sample, which was stored in the up/down
counter as a binary number, The up/down counter is incremented or
decremented depending on whether the previous sample is larger or smaller than
the current sample. The up/down counter is clocked at a rate equal to the sample
rate. Therefore, the up/down counter is updated after each comparison.
Block Diagram:
Fig: 1 Delta Modulation Circuit
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Fig: 2 Delta Demodulation Circuit
Procedure:
1. Switch on the experimental board.
2. Connect the clock signal of frequency of 10KHz,with amplitude of 5v(p-p)
to the delta modulator circuit.
3. Connect the modulating signal of amplitude 5v(p-p) and frequency of of
0.2KHz modulating input of the delta modulator
And observe the same on channel 1 of a Dual Trace oscilloscope.
4. Observe the Delta Modulator output on channel 2.
5. Connect this Delta modulator output to the Demodulator
6. Also connect the clock signal to the demodulator.
7. Observe the Demodulator output with and without RC filter on CRO.
Model Waveforms:
(a)
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(b)
(c)
Fig: 3 Waveforms (a) Clock input (b) Delta modulation output & message signal
(c) D/A converter output
Inference:
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Questions:
1. What is the slope overload effect?
2. What is granular noise?
3. Write the advantage of DM over PCM?
4. What is the effect of the Low Pass Filter cut off frequency on output of
demodulator?
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5. FREQUENCY SHIFT KEYING
Aim:
To generate the waveforms of frequency shift keying
Apparatus required:
Name of the apparatus
Specifications/Range
Quantity
33kΩ
2
0.01µF, 100pF
Each one
0-1MHz
1
RPS
0-30V, 1A
1
CRO
0-30MHz
1
Supply voltage - ±18V or 36V
Power dissipation – 750mW
----
1
Resistors
Capacitors
Function Generator
IC 8038
CRO Probes
1
Theory:
FSK signaling schemes find a wide range of applications in low-speed digital
data transmission system. FSK schemes are not as efficient as PSK interms of
power and bandwidth utilization. In binary FSK signaling the waveforms are used
to convey binary digits 0 and 1 respectively. The binary FSK waveform is a
continuous, phase constant envelope FM waveform. The FSK signal bandwidth
in this case is of order of 2MHz, which is same as the order of the bandwidth of
PSK signal.
Circuit Diagram:
Fig: 1 Frequency Shift Keying
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Procedure:
1. Connect the circuit as shown in fig.1
2. Apply the (binary) Data input of amplitude 20V (p-p) with frequency of 6 KHz
from function generator to pin no.7.
3. Give the power supply of 10v to the appropriate pins.
4. Observe the FSK output at pin no.2.
5. Now note down the mark and space frequencies for different carrier
frequencies.
6.
Calculate the maximum frequency deviation and modulation index.
7. Repeat the steps (5) and (6) for different pulse durations of binary input.
Model Waveforms:
(a)
(b)
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(c)
Fig: 2 Waveforms of (a) Carrier wave (b) Data input (c) FSK Wave
Inference:
Questions:
1. Write the advantage of FSK compared to ASK?
2. What is the disadvantage of FSK compared with ASK & PSK?
3. What is the effect of R1, C2 values on the output?
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6. PHASE SHIFT KEYING
Aim:
To generate the waveforms of phase shift keying.
Apparatus required:
Name of the apparatus
Specifications/Range
Quantity
Diodes(IN4007)
Max Voltage:45V
4
Transformers
7V-0-7V
2
Function Generator
0-1MHz
2
CRO
0-30MHz
1
CRO Probes
----
1
Theory:
Circuit diagram of PSK as shown in Fig.1. The phase of carrier is shifted between
two values is called Phase Shift Keying. The amplitude of carrier remains
constant. Phase Shift Keying is also called Phase Reversal Keying. The
performance of PSK is more than ASK. PSK is a non linear modulation. PSK
needs a complicated. Synchronous circuit at the receiver. The bandwidth of PSK
is 2f m.
Circuit Diagram:
Fig: 1 Phase Shift Keying Circuit
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Procedure:
1. Switch on the experimental board.
2. Apply the carrier signal of amplitude7v (p-p) with frequency of 4 KHz to the
modulator input and observe the signal on the channel of the CRO.
3. Apply the modulating signal of amplitude 6V (p-p) and frequency of 0.5 KHz
to pin.11.
4. Observe the output of PSK modulator on the channel 2 of the CRO.
Model Waveforms:
(a)
(b)
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(c)
Fig: 2 Waveforms of (a) Carrier signal (b) Modulating signal (c) PSK output
Inference:
Questions:
1. Drawback of DPSK compared to BPSK?
2. Write the advantage of BPSK over the BPSK?
3. What is the effect of carrier amplitude on the output?
4. What is the effect of modulating signal frequency on the output?
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7. DIFFERENTIAL PHASE SHIFT KEYING MODULATION
AND DEMODULATION
Aim:
To study the various steps involved in generating the differential phase
shift keyed signal and the binary signal from the received DPSK signal
Apparatus required:
1. DPSK trainer board
2. Cathode Ray Oscilloscope (0-30MHz)
Theory:
The differentially coherent PSK signaling scheme make use of a technique
designed to get around the need for a coherent reference signal at the receiver.
In the DPSK scheme, the phase reference for demodulation is derived from the
phase of the carrier during the preceding signaling interval, and the receiver
decodes the digital information based on the differential phase.
Circuit Diagram:
Fig: 1 Differential Phase Shift Keying Circuit
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Procedure:
1. Switch on the experimental board.
2. Check the carrier signal and the data generator signals initially.
3. Apply the carrier signal of amplitude 6v (p-p) with frequency of1KHz to the
carrier input, the data input of amplitude 5v (p-p) with frequency of 600Hz
to the data input and bit clock of amplitude 5v (p-p) with and frequency of
1 KHz to the DPSK modulator.
4. Observe the DPSK wave of amplitude 5.6v (p-p) and frequency of 1 KHz
with respect to the input data generated signal of dual trace oscilloscope.
5. Give the output of the DPSK modulator signal to the input of demodulator,
give the bit clock output to the bit clock input to the demodulator and also
give the carrier output to the carrier input of demodulator.
6. Observe the demodulator output with respect to data generator signal.
Model Waveforms:
(a)
(b)
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(c)
(d)
(e)
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Fig: 2 Waveforms of (a) Carrier signal (b) Bit clock (c) Data input (d) Differential
data (e) DPSK wave
Inference:
Questions:
1. Write the advantage of DPSK?
2. What is the drawback of DPSK compared to PSK system?
3. What is the effect of carrier amplitude on the output of DPSK?
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8. COMPANDING
Aim:
1. Study and analysis of µ-Law Compressor and Decompressor.
2. Study and analysis of A-Law Compressor and Decompressor.
Apparatus:
1.
Companding Trainer Kit (Techbook ST2805)
2.
Regulated Power Supply
3.
Oscilloscope/DSO
4.
Test probe
Theory:
Companding:
In digital Companding, the analog signal is first sampled and converted to a
linear PCM code and then the linear code is digitally compressed. In receiver, the
compressed PCM code is expanded and then decoded (i.e., converted back to
analog). The encoded representation of µ255 PCM code words use a signmagnitude format wherein 1 bit identifies the sample polarity and the remaining
bits specify the magnitude of the sample. The 7 magnitude bits are conveniently
partitioned into a 3-bit segment identifier (S) and 4-bit quantizating step identifier
(Q). Thus, the basic structure of an 8-bit µ255 PCM codeword is shown in figure.
Polarity bit (P) =
0 for positive sample values
1 for negative sample values
Compressor:
The compression process is as follows. The analog signal is sampled and
converted to a linear 14-bit sign-magnitude code(1-bit(MSB) as sign bit and other
13-bits as magnitude bits). The sign bit is transferred directly to an eight-bit
compressed code. The segment number in the eight-bit code is determined by
counting the number of leading 0s in the 13-bit magnitude portion of the linear
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code beginning with the most significant bit. Subtract the number of leading 0s
(not to exceed 7) from 7. The results the segment number, which is converted to
a three-bit binary number and inserted into the eight-bit compressed code as the
segment identifier. The four magnitude bits (a, b, c and d) represent the
quantization interval (i.e., subsegments) and are substituted into the least
significant four bits of the 8-bit compressed code.
In the given table using only magnitude bits.
µ-Law Binary Encoding Table:
Essentially, the expander guesses what the truncated bits were prior to
compression.
µ-Law Binary Decoding Table:
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A-Law Companding:
A-law is the CCITT recommended companding standard used across Europe.
Limiting sample values to 12 magnitude bits. In digital companding, the analog
signal is first sampled and converted to a linear PCM code and then the linear
code is digitally compressed. In receiver, the compressed PCM code is
expanded and then decoded (i.e., converted back to analog). The eight-bit
compressed code consists of a sign bit, a three-bit segment identifier, and a fourbit quantization interval.
The compression process is as follows. The analog signal is sampled and
converted to a linear 13-bit sign-magnitude code (1-bit (MSB) as sign bit and
other 12-bits as magnitude bits). The sign bit is transferred directly to an eight-bit
compressed code. The segment number in the eight-bit code is determined by
counting the number of leading 0s in the 12-bit magnitude portion of the linear
code beginning with the most significant bit. Subtract the number of leading 0s
(not to exceed 7) from 7. The results the segment number, which is converted to
a three-bit binary number and inserted into the eight-bit compressed code as the
segment identifier. The four magnitude bits (a, b, c and d) represent the
quantization interval (i.e., subsegments) and are substituted into the least
significant four bits of the 8-bit compressed code.
A-Law Binary Encoding Table:
Essentially, the expander guesses what the truncated bits were prior to
compression.
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A-Law Binary Decoding Table:
Block Diagrams:
µ-Law Companding
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A-Law Companding
Procedure (µ-Law):
Step 1: Connect and switch on the power supply of ST2805.
Step 2: Select µ-Law Companding using switch. Move switch towards right.
Step3: Connect CN3 to CN1 or CN2 for input Selection. If CN3 connected to
CN1 then internally generated Signal (Sine Wave) will be selected as
input. If CN3 connected to CN2 then Dip input will be selected. So user
can select input using DIP Switches.
Step 4: User can match compressed output and decompressed output for
respective input using given table.
Observations:
● Observe the internally generated input signal at TP1.
● Observe the binary bits of selected input signal on led at 12 bit register linear
code.
● Observe the sign bit of compressed output at TP2.
● Observe the binary bits of segment identifier of compressed output at TP3,
TP4, and TP5.
● Observe the binary bits of Quantization interval of compressed output at TP6,
TP7, TP8, and TP9.
● Observe the analog compressed output at TP10 and binary bits on led at
compressed data.
● Observe the sign bit of decompressed output at TP11.
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● Observe the binary bits of segment identifier of decompressed output at TP12,
TP13, and TP14.
● Observe the binary bits of Quantization interval of decompressed output at
TP15, TP16, TP17, and TP18.
● Observe the analog decompressed output at TP19 and binary bits on led at
Decompressed data.
Table for verification of compressor and decompressor output wrt. Input selection
using DIP switch.
Model Waveforms:
Real time output of µ-Law Compressor and decompressor on DSO when sine
wave is selected as input signal
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CH1: Sine Wave as Input (TP1)
CH2: Compressed Signal (TP10)
CH1: Sine Wave as Input (TP1)
CH2: Decompressed Signal (TP19)
CH1: Compressed Signal (TP10)
CH2: Decompressed Signal (TP19)
Procedure (A-Law):
Step 1: Connect and switch on the power supply of ST2805.
Step 2: Select A-Law Companding using switch. Move switch towards left.
Step 3: Connect CN3 to CN1 or CN2 for input Selection. If CN3 connected to
CN1 then internally generated Signal (Sine Wave) will be selected as
input. If CN3 connected to CN2 then Dip input will be selected. So user
can select input using DIP Switches.
Step 4: User can match compressed output and decompressed output for
respective input using given table.
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Observations:
● Observe the internally generated input signal at TP1.
● Observe the binary bits of selected input signal on led at 12 bit register linear
code.
● Observe the sign bit of compressed output at TP20.
● Observe the binary bits of segment identifier of compressed output at TP21,
TP22, and TP23.
● Observe the binary bits of Quantization interval of compressed output at TP24,
TP25, TP26, and TP27.
● Observe the analog compressed output at TP28 and binary bits on led at
compressed data.
● Observe the sign bit of decompressed output at TP29.
● Observe the binary bits of segment identifier of decompressed output at TP30,
TP31, and TP32.
● Observe the binary bits of Quantization interval of decompressed output at
TP33, TP34, TP35, and TP36.
● Observe the analog decompressed output at TP37 and binary bits on led at
Decompressed data.
Table for verification of compressor and decompressor output wrt input
selection using DIP switch.
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Model Waveforms:
Real time output of A-Law Compressor and decompressor on DSO when sine
wave is selected as input signal
CH1: Sine Wave as Input (TP1)
CH2: Compressed Signal (TP28)
CH1: Sine Wave as Input (TP28) CH2: Decompressed Signal (TP37)
CH1: Compressed Signal (TP1)
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9. LINEAR BLOCK CODE - ENCODER & DECODER
Aim:
To Study the Hamming Code 7-bit Generation.
Apparatus:
1.
Linear Block Code- Encoder & Decoder Trainer Kit (Scientech 2121A &
2121B)
2.
2 mm Banana Cable
3.
Regulated Power Supply
Theory:
Error Detection and Correction:
Error detection is the ability to detect the presence of errors caused by noise or
other impairments during transmission from the transmitter to the receiver. Error
correction is the additional ability to reconstruct the original, error-free data.
There are two basic ways to design the channel code and protocol for an error
correcting system.
Linear block codes:
Linear block codes are conceptually simple codes that are basically an extension
of single-bit parity check codes for error detection. A single-bit parity check code
is one of the most common forms of detecting transmission errors. This code
uses one extra bit in a block of n data bits to indicate whether the number of 1s in
a block is odd or even. Thus, if a single error occurs, either the parity bit is
corrupted or the number of detected 1s in the information bit sequence will be
different from the number used to compute the parity bit: in either case the parity
bit will not correspond to the number of detected 1s in the information bit
sequence, so the single error is detected. Linear block codes extend this notion
by using a larger number of parity bits to either detect more than one error or
correct for one or more errors. Unfortunately linear block codes, along with
convolutional codes, trade their error detection or correction capability for either
andwidth expansion or a lower data rate, as will be discussed in more detail
below. We will estrict our attention to binary codes, where both the original
information and the corresponding code consist of bits taking a value of either 0
or 1.
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Block Diagram:
Procedure:
1.
Connect the power supply mains cord to the Scientech 2121A and
Scientech 2121B but do not turn ON the power supply until connections
are made for this experiment.
2.
Keep default/manual switch in Manual mode.
3.
There are some conditions regarding H-Matrix selection manually which
are:
a. Any row should not be identically selected like there should not all 1’s
or all 0’s.
b. Each row selection should be different from other row.
c. The matrix should be so chosen that all the rows are distinct and
consist of at least three 1’s in them.
4.
Switch ‘On’ the power supply and press reset button.
5.
Check the clock pulse of 2 KHz on Oscilloscope at given test point.
6.
At Scientech 2121A Block Code Encoder unit now select the data at
seven Segment display with the help of BCD (binary coded decimal)
switch.
7.
Check the data at seven segment display and its binary equivalent (d3,
d2, d1, d0), in the Code Word Generator block T where bit pattern is
selected in the form of 8, 4, 2, 1 format.
8.
Now set the H matrix are per the condition given in step 3. In Observation
Table 3.1, some example sets are given (Set 1, Set2, Set3 and Set4).
You can set your own matrix or you can choose any set from example
sets and select the H Matrix as per the table.
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9.
After that check the H matrix in the form of H= [Ik] [P]; Identity matrix and
Parity matrix corresponding to the selected set as given in the
Observation Table 3.1.
10.
Check the massage signal in the form of (d3, d2, d1, d0, p3, p2, p1) and
verify the status of ‘Parity Bits’ (p3, p2, p1) as per the equations given for
parity generation (see bservation Table 3.1).
11.
Connect 2mm patch cords between horizontal bit stream and p/s block as
per the connections diagram.
12.
Observe the bit pattern output of codeword Generator at vertical 7-bit
stream.
13.
Now connect the Data output to the Data In of 2121B which is block code
decoder.
14.
Now connect the clock and ground of 2121A to 2121B via a 2mm patch
cord.
15.
Now set the H-Matrix section of 2121B Block code Decoder unit as per
the same set what you have chose for 2121A Encoder unit. Refer the
Observation Table 3.1.
16.
Now first set Data ‘0’ at Encoder unit and press reset switch until you get
same decoded data on LED display and as well as at the seven segment
display in numeric form. Once you get the same data 0 at decoder unit
you can vary BCD switch to get the sequential data from 0-9.
17.
For any selected data from 0-9, check the H matrix in the form of H= [P]
[Ik]; Parity matrix and Identity matrix as given in the Observation Table
3.1
18.
Also check the massage signal in vertical matrix ‘R’ in the form of (d3, d2,
d1, d0, p3, p2, p1) and check the status of Syndrome Em. As there is no
error in the bits it will show (0 0 0).
19.
Check the corrected code word and match it with the code word of
Encoder unit.
20.
Also check the Decode Bits (d3, d2, d1, d0) and match with the data at
Encoder unit.
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Equations for Parity Generation:
Code Word Generator:
Observation Table:
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10. BINARY CYCLIC CODE- ENCODER AND
DECODER
Aim:
To study the Binary Cyclic Encoding and Decoding and to verify the input and
output.
Apparatus Required:
1. ST2120 Error Detection & Correction Cyclic Codes Kit.
2. 2 mm Banana cable
3. Cathode Ray Oscilloscope
Theory:
The linear code C of length n is a cyclic code if it is invariant under a cyclic Cyclic
code shift:
if and only if
As C is invariant under this single right cyclic shift, by iteration it is invariant under
any number of right cyclic shifts. As a single left cyclic shift is the same as n-1
right cyclic shifts, C is also invariant under a single left cyclic shift and hence all
left cyclic shifts. Therefore the linear code C is cyclic precisely when it is invariant
under all cyclic shifts.
Encoder Diagram:
Fig.: Encoder for (7, 4) Cyclic Code Generator by g(x) =1+x2+x3
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Table: Register Contents of Encoder
Block Diagram:
Procedure:
1. Connect the power supply mains cord to the ST2120, but do not turn ON
the power supply until connections are made for this experiment.
2. From Clock Section, connect 16 KHz Clock output to Clock Generator
(Clock input).
3. Connect the Data Clock of clock generation section to Data Clock of Data
Source.
4. Connect the Data Out of Data Source to Data In of Cyclic Encoder.
5. Connect the Code Clock of Clock Generation section to Code Clock of
Cyclic Encoder.
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6. Switch ‘On’ the power supply and oscilloscope.
7. Observe the bit pattern of Code Word output of Cyclic Encoder. The bit
stream is a repeating 8 bit serial sequence of the input data selected
through BCD switches.
8. Change input data through BCD switches and observe the output of
Cyclic Encoder.
9. Now connect the Code Word output of Cyclic Encoder to Decoder and
output of Decoder to Input of display.
10. Change the clock input to 8 KHz to 1 KHz and then observe the data
output.
Observations:
1. The data output of Data Source is a repeating sequence of input data
selected through BCD switches.
2. The 8 bits of output data are binary coded decimal values on BCD
switches.
3. The output data rate of Data Sources is selected through the input data
clock.
4. Encoded and decoded data stream is same as observed on segmental
display.
Result:
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1. AMPLITUDE SHIFT KEYING
Aim:
To generate the waveforms of Amplitude Shift Keying.
Apparatus required:
Name of the Apparatus
Specifications/Range
Quantity
Resistors
1.2KΩ,
3
Transistor
BC 107
2
CRO
30MHz
1
Function generator
0-1MHz
1
Regulated Power Supply
0-30V, 1A
1
CRO Probes
---
1
Theory:
The binary ASK system was one of the earliest form of digital modulation used in
wireless telegraphy. In an binary ASK system binary symbol 1 is represented by
transmitting a sinusoidal carrier wave of fixed amplitude Ac and fixed frequency fc
for the bit duration Tb where as binary symbol 0 is represented by switching of the
carrier for Tb seconds. This signal can be generated simply by turning the carrier
of a sinusoidal oscillator ON and OFF for the prescribed periods indicated by the
modulating pulse train. For this reason the scheme is also known as on-off shift
testing. Let the sinusoidal carrier can be represented by Ec (t) =Ac cos (2Πfct)
then the binary ASK signal can be represented by a wave s(t) given by S(t) =
Accos(2Πf ct), symbol 1 ASK signal can be generated by applying the incoming
binary data and the sinusoidal carrier to the two inputs of a product modulator.
The resulting output is the ASK wave. The ASK signal which is basically product
of the binary sequence and carrier signal has a same as that of base band signal
but shifted in the frequency domain by ±fc. The band width of ASK signal is
infinite but practically it is 3/Tb.
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Circuit Diagram:
Fig: 1 Amplitude Shift Keying Circuit
Procedure:
1. Connect the circuit as per the circuit diagram.
2. Switch on the supply.
3. Apply the sinusoidal carrier signal from the function generator to the collector
terminal of the transistor with 10v (p-p) amplitude and10KHz frequency.
4. Apply the Binary signal from the pulse generator to the Base terminal of the
transistor with 5v (p-p) amplitude and 2 KHz frequency.
5. Observe the output of ON/OFF keying from ASK modulator circuit using CRO.
6. Now vary the Amplitude and frequency of the binary signal and observe the
output changes of ASK modulated Wave & compare it with the modulating
data signal applied to the modulator input.
Model Waveforms:
(a)
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(b)
Fig: 2 Waveforms of (a) Carrier signal (b) Data signal & ASK wave
Questions:
1. Why we are not preferred ASK over PSK and FSK?
2. What is another name of ASK modulation scheme?
3. What is the Effect of carrier amplitude, frequency, V cc on the output?
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2. TIME DIVISION MULTIPLEXING AND
DEMULTIPLEXING
Aim:
1. To study the 4 channel analog multiplexing and de multiplexing
2. To study the effect of sampling frequency on output signal
characteristics.
Apparatus Required:
1. Time Division Multiplexing & De multiplexing (Digital) Trainer Kit
(Or)
a. Data Generator IC 7490
b. 8-1 Multiplexer IC 74151
c. 3-bit Address Generator IC 74163
d. 1-8 De multiplexer IC 74138
e. Clock Generator IC 555
f.
DC Regulated Power Supply +5V.
2. Set of Patch chords
3. Dual Trace Cathode Ray Oscilloscope.
Theory:
8 TO 1 MULTIPLIXER
For this Multiplexing process, 8 bit Digital Multiplexer 74151 IC is used. L1 to L8
are the 8 input channels, data Multiplexed is given to them. A0, A1 and A2 are
the address data finder. Depending upon the address data at any instant, input
channel corresponding to the address location is multiplexed. For example, if the
address bit is 101, channel L6 is multiplexed at that instant.
1 TO 8 DE MULTIPLEXER
For this De multiplexing process, 74138 digital De multiplexer IC is used. L1 to
L8 are the corresponding. 8-channel outputs, which are in synchronization to the
multiplexed channels ar multiplexing process. The address data generator for
both Multiplexer and De multiplexer is same. So both Multiplexer and
Demultiplexer are in synchronization.
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Block Diagram:
Procedure:
1. Switch ‘ON’ the experimental kit.
2. Observe the MSB bit of the address generator to one channel of a dual
trace CRO and trigger the CRO w.r.t . the same channel.
3. Observe the output of the 8-1 line multiplexer on the second channel of
the CRO.
4. Apply a low (GND) signal to the 8 multiplexing input one by one and
observe how the total time is divided by each channel w.r.t. the address
generator. Fig.2 shows the working principle.
5. Now connect the 8-1 line multiplexer to the 1-8 line demultiplexer.
6. Give any data available from the data generator to any multiplexing input
and observe the output at corresponding demultiplexer output.
Ex. Suppose if we are giving input at L1 input, observe the output of the
Demultiplexing output at L1 only.
7. Now connect different data to the different inputs and observe the outputs
at corresponding demultiplexed outputs and compare the multiplexing
inputs and corresponding demultiplexed outputs.
8. Data provided at D1 is not multiplexed because its frequency is greater
than the Address generators frequency (sampling theorem).
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Model Output Waveforms:
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3. BINARY AMPLITUDE SHIFT KEYING
MODULATION AND DEMODULATION
Aim:
To Generate the Amplitude Shift Keying Modulation and Demodulation signals
using MATLAB 7.0.4
Apparatus required: Software MATLAB7.0.4
Algorithm:
Step1: The binary sequence is taken as input into a variable.
Step2: The carrier signal with required frequency is selected.
Step3: The required carrier wave is generated.
Step4: The input binary data is given to serial to parallel converter.
Step5: The parallel sequence is converted to analog signal using D/A converter.
Step6: The analog signal is combined with the generated carrier signal.
Step7: The required ASK signal is generated.
Step8: (Detection) The ASK wave is combined with the carrier wave.
Step9: The output is given to the comparator circuit.
Step10: The output is converted into digital by using A/D converter.
Step11: This gives us the binary sequence as the output of the demodulator.
Block diagrams:
BASK MODULATOR
BASK DEMODULATOR
Program:
%Matlab program for ASK wave
clc;
clf;
clear all;
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close all;
b=input('enter binary data:');
fc=4000;
t=linspace(0,1/1000,50);
ec=cos(2*pi*fc*t);
ook=[ ];
bin=[ ];car=[ ];
for i=1:length(b);
ook=[ook,b(i)*ec];
bin=[bin,b(i)*ones(1,50)];
car=[car,ec];
end
%ASK detection
balout=[ ];%sync det output
demod=[ ];%demodulation output
for i=1:length(ook);
balout=[balout,car(i)*ook(i)];
end;
for i=1:50:length(ook);
if sum(balout(i):balout(i+49))>0.5
demod=[demod,ones(1,50)];
else demod=[demod,zeros(1,50)];
end;
end;
%ploting the graph
subplot(5,1,1);
plot(ec,'linewidth',2);
title('carrier');
xlabel('time');
ylabel('amplitude');
subplot(5,1,2);
plot(0:length(bin)-1,bin,'k','linewidth',2);
title('input data');
xlabel('time');
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ylabel('amplitude');
subplot(5,1,3);
plot(ook,'r-','linewidth',2);
title('modulated data');
xlabel('time');
ylabel('amplitude');
subplot(5,1,4);
plot(balout,'r-','linewidth',2);
title('balanced modulator data');
xlabel('time');
ylabel('amplitude');
subplot(5,1,5);
plot(demod,'r-','linewidth',2);
title('demodulated output data');
xlabel('time');
ylabel('amplitude');
Model Output Waveforms:
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4. BINARY PHASE SHIFT KEYING
MODULATION AND DEMODULATION
Aim:
To Generate the Binary Phase Shift Keying Modulation and Demodulation
signals using MATLAB 7.0.4
Software required: MATLAB7.0.4
Algorithm:
Step1: The binary sequence is taken as input into a variable.
Step2: This binary data is converted into the polar form either in RZ or NRZ form.
Step3: The carrier signal with required frequency is selected.
Step4: The required carrier wave is generated.
Step5: Both carrier and the binary data is given to the balanced modulator circuit.
Step6: The balanced modulator output gives us the BPSK waveform.
Step7: (Demodulator) The BPSK wave is given to the multiplier along with the
carrier signal.
Step8: The multiplier output is passed through the low pass filter.
Step9: This gives us the binary sequence as the output of the demodulator.
Block diagram:
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Program:
%Matlab program for BPSK wave
clc;
clf;
clear all;
close all;
b=input('enter binary data:');
fc=4000;
t=linspace(0,1/1000,50);
ec=cos(2*pi*fc*t);
pskout=[ ];
bin=[ ];car=[ ];
for i=1:length(b);
if b(i)==1
pskout=[pskout,b(i)*ec];
else pskout=[pskout,(b(i)-1)*ec];
end;
bin=[bin,b(i)*ones(1,50)];
car=[car,ec];
end
%BPSK detection
balout=[ ];%sync det output
demod=[ ];%demodulation output
for i=1:length(pskout);
balout=[balout,car(i)*pskout(i)];
end;
for i=1:50:length(pskout);
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if sum(balout(i):balout(i+49))>0
demod=[demod,ones(1,50)];
else demod=[demod,zeros(1,50)];
end;
end;
%ploting the graph
subplot(5,1,1);
plot(ec,'linewidth',3);
title('carrier');
xlabel('time');
ylabel('amplitude');
subplot(5,1,2);
plot(0:length(bin)-1,bin,'k','linewidth',3);
title('input data');
xlabel('time');
ylabel('amplitude');
subplot(5,1,3);
plot(pskout,'r-','linewidth',3);
title('BPSK output');
xlabel('time');
ylabel('amplitude');
subplot(5,1,4);
plot(balout,'r-','linewidth',3);
title('balanced modulater data');
xlabel('time');
ylabel('amplitude');
subplot(5,1,5);
plot(demod,'r-','linewidth',3);
title('Demodulated output');
xlabel('time');
ylabel('amplitude');
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Model Output Waveforms:
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5. FREQUENCY SHIFT KEYING MODULATION
AND DEMODULATION
Aim:
To Generate the Frequency Shift Keying Modulation and Demodulation signals
using MATLAB 7.0.4
Software required: MATLAB7.0.4
Algorithm:
Step1: The binary input bit sequence is taken and stored into a variable.
Step2: The carrier frequencies for both low frequency and high frequency bits are
selected and the respective carriers are generated.
Step3: The input bits are given separately to two level shifters as one as the
direct bits and for another through the inverter.
Step4: Both the level shifter outputs are multiplied with the respective carrier
(High frequency carrier for bit ‘1’ and low frequency carrier for bit’0’).
Step5: Both the multiplier outputs are added up to get the output FSK wave form.
Step6: In the FSK detector process at first the input FSK wave is given to the
band pass filter and then passed through the limiting circuit.
Step7: The limiting circuit output is given to the FM detector circuit.
Step8: The FM detector output is then passed through low pass filter which acts
as an integrator that adds up all the values of the signal.
Step9: The low pass filter output is then given to the decision device which gives
us the output as the input bit stream.
Block diagrams:
Binary FSK Transmitter:
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Binary FSK Receiver
Program:
%Matlab program for FSK wave
clc;
clf;
clear all;
close all;
b=input('enter binary data:');
f1=4000;f2=12000;
t=linspace(0,1/4000,50);
ec1=cos(2*pi*f1*t);
ec2=cos(2*pi*f2*t);
fskout=[ ];
bin=[ ];car1=[ ];car2=[ ];
for i=1:length(b);
if b(i)==1
fskout=[fskout,b(i)*ec2];
else fskout=[fskout,(1-b(i))*ec1];
end;
bin=[bin,b(i)*ones(1,50)];
car1=[car1,ec1];
car2=[car2,ec2];
end
%FSK detection
bal1=[ ];bal2=[ ];demod=[ ];
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for i=1:length(fskout);
bal1=[bal1,car1(i)*fskout(i)];
bal2=[bal2,car2(i)*fskout(i)];
end;
for i=1:50:length(fskout);
sum1=0,sum2=0;sum=0;
for i=i:i+49
sum1=sum1+bal1(i);
sum2=sum2+bal2(i);
end;
sum=-sum1+sum2;
if sum>0
demod=[demod,ones(1,50)];
else
demod=[demod,zeros(1,50)];
end;
end;
%ploting the graph
subplot(5,1,1);
plot(car1,'linewidth',3);
title('carrier 1');
xlabel('time');
ylabel('amplitude');
subplot(5,1,2);
plot(car2,'linewidth',3);
title('carrier 2');
xlabel('time');
ylabel('amplitude');
subplot(5,1,3);
plot(0:length(bin)-1,bin,'k','linewidth',3);
title('input data');
xlabel('time');
ylabel('amplitude');
subplot(5,1,4);
plot(fskout,'r-','linewidth',3);
title('FSK output');
xlabel('time');
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ylabel('amplitude');
subplot(5,1,5);
plot(demod,'r-','linewidth',3);
title('Demodulated output');
xlabel ('time');
ylabel ('amplitude');
Model Output Waveforms:
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6. QUADRATURE PHASE SHIFT KEYING
MODULATION AND DEMODULATION
Aim:
To Generate the Quadrature phase Shift Keying Modulation and Demodulation
signals using MATLAB 7.0.4
Software required:
MATLAB7.0.4
Algorithm:
Step1: The binary bit sequence is first taken into a variable.
Step2: The suitable carrier frequency is selected and two carriers one with zero
phase and other with 90o phase are generated.
Step3: The input bit stream is given to the de-multiplexer and is decoded.
Step4: The de-multiplexer output is divided into two and one is multiplied with in
phase component and the other with the out of phase component.
Step5: Both the multiplexer outputs are taken and are added together which
gives us the QPSK output wave.
Step6: In the de-modulation process the input QPSK wave is multiplied with both
the in phase and out phase components by an multiplier.
Step7: Both the outputs are passed through an low pass filter which acts as an
integrator that adds up all the values of the signal.
Step8: The low pass filter outputs are given to the decision device which assigns
the values to the wave.
Step9: The decision device output is given to the multiplexer circuit which gives
the output as the input bit stream.
Block Diagrams:
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Program:
%Matlab program for QPSK wave
clc;
clf;
clear all;
close all;
b=input('enter binary data:');
fc=4000;
t=linspace(0,1/4000,50);
ec2=cos(2*pi*fc*t);
ec1=sin(2*pi*fc*t);
qpskout=[ ];bin=[ ];car1=[ ];car2=[ ];be=[ ];bo=[ ];bal1=[ ];bal2=[ ];
for i=1:length(b);
bin=[bin,b(i)*ones(1,50)];
car1=[car1,ec1];
car2=[car2,ec2];
if mod(i,2)==0
if b(i)==0
be=[be,-ones(1,100)];
else be=[be,ones(1,100)];
end;
bal1=[bal1,be(i*50-1)*ec1,be(i*50-1)*ec1];
else
if b(i)==1
bo=[bo,ones(1,100)];
else bo=[bo,-ones(1,100)];
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end;
bal2=[bal2,bo(i*50-1)*ec2,bo(i*50-1)*ec2];
end;
end;
for i=1:2:length(b)
if b(i)==0 && b(i+1)==0
qpskout=[qpskout,-ec1-ec2,-ec1-ec2];
elseif b(i)==0 && b(i+1)==1
qpskout=[qpskout,-ec1+ec2,-ec1+ec2];
elseif b(i)==1 && b(i+1)==0
qpskout=[qpskout,ec1-ec2,ec1-ec2];
else
qpskout=[qpskout,ec1+ec2,ec1+ec2];
end;
end;
%ploting the graph
subplot(4,1,1);
plot(bin,'linewidth',3);
title('binary data');
xlabel('time');
ylabel('amplitude');
subplot(4,1,2);
plot(be,'r','linewidth',3);
title('even data');
xlabel('time');
ylabel('amplitude');
subplot(4,1,3);
plot(bo,'g','linewidth',3);
title('odd data');
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xlabel('time');
ylabel('amplitude');
subplot(4,1,4);
plot(car1,'linewidth',3);
title('carrier 1');
xlabel('time');
ylabel('amplitude');
figure;
subplot(4,1,1);
plot(car2,'linewidth',3);
title('carrier2');
xlabel('time');
ylabel('amplitude');
subplot(4,1,2);
plot(bal1,'r','linewidth',3);
title('bal mod 1 data');
xlabel('time');
ylabel('amplitude');
subplot(4,1,3);
plot(bal2,'g','linewidth',3);
title('bal mod 2 data');
xlabel('time');
ylabel('amplitude');
subplot(4,1,4);
plot(qpskout,'linewidth',3);
title('modulated');
xlabel('time');
ylabel('amplitude');
%demodulation of qpsk
demod1=[ ];demod2=[ ];demod=[ ];synd1=[ ];synd2=[ ];
for i=1:length(qpskout);
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synd1=[synd1,car1(i)*qpskout(i)];
synd2=[synd2,car2(i)*qpskout(i)];
end;
for i=1:100:length(qpskout);
sum1=0;sum2=0;
for i=i:i+99
sum1=sum1+synd1(i);
sum2=sum2+synd2(i);
end;
if sum1 > 0
demod1=[demod1,ones(1,50)];
else
demod1=[demod1,zeros(1,50)];
end;
if sum2 > 0
demod2=[demod2,ones(1,50)];
else
demod2=[demod2,zeros(1,50)];
end;
end;
demod1
demod2
for i=1:50:length(demod1);
demod=[demod,demod1(i:i+49),demod2(i:i+49)];
end;
%ploting the graph
figure;
subplot(3,1,1)
plot(synd1,'linewidth',3);
title('sync detector 2');
xlabel('time');
ylabel('amplitude');
subplot(3,1,2)
plot(synd2,'r','linewidth',3);
title('sync detector 2');
xlabel('time');
ylabel('amplitude');
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subplot(3,1,3)
plot(demod,'g','linewidth',3);
title('demodulated');
xlabel('time');
ylabel('amplitude');
Model Output Waveforms:
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APPENDIX
Name of the
component
Important Specifications
Pin Diagram
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
74LS00
Operating temperature Range – 0oC to
+70oC
Output Current High max - -0.4mA
Output Current Low Max- 80mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
74LS08
Operating temperature Range – 0oC to
+70oC
Output Current High Max - -0.4mA
Output Current Low Max- 80mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
74LS74
+70oC
Power supply current - 8.0mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
74138
Operating temperature Range – 0oC to
+70oC
Output Current High Max - -0.4mA
Output Current Low Max- 80mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
74194
+70oC
Output Current High max - -0.4mA
Output Current Low max - 80mA
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Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
High level input voltage min – 2V
Low level input voltage max– 0.8V
74LS374
High level output current max – -2.4mA
Low level output current max- 24mA
Operating temperature Range – 0oC to
+70oC
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
74151
+70oC
Output Current High max - -0.4mA
Output Current Low max - 80mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
+70oC
Output Current High max - -0.4mA
74LS163
Output Current Low max - 80mA
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Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
+70oC
74LS164
Output Current High max - -0.4mA
Output Current Low max - 80mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Free air operating temperature- 0oC to
+70oC
74165
Supply Current max – 36mA
Clock frequency – 25MHz
Pulse width (Clock) – 25ns
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
+70oC
Power supply current – 34mA
74168
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Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
74193
+70oC
Clock frequency – 25MHz
Supply Current max – 34mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
74LS86
+70oC
Output Current High max - -0.4mA
Output Current Low max - 80mA
Supply Voltage Min – 4.75V
Supply Voltage Max – 5.25V
Operating temperature Range – 0oC to
74LS90
+70oC
Output Current High max - -0.4mA
Output Current Low max - 80mA
Input voltage Range - -14.5V to 13V
Voltage gain – 40V/mV
LM311
Saturation voltage – 1.5V
Positive Supply Current – 7.5mA
Negative Supply Current – 5mA
Wide power supply rating – 3V to 32V
Operating temperature Range – 0oC to
+70oC
LM324
Storage temperature - (-65oC to +150oC)
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Supply Voltage – 5V
Operating temperature Range – (-55oC to
+125oC)
DAC0800
Power Dissipation -500mW
Input current – 5mA
Storage temperature - (-65oC to +150oC)
Supply voltage – ±5V
Clock range – 50 to 800KHz
Operating temperature Range – (-55oC to
ADC0800
+125oC)
Power supply current – 20mA
Supply voltage - +5V to 18V
Operating temperature Range – (-40 oC to
+80oC)
CD4051
Storage temperature - (-65 oC to +150oC)
Power dissipation – 700mW
Supply voltage - +5V to 18V
Operating temperature Range – (-40 oC to
+80oC)
CD4052
Storage temperature - (-65 oC to +150oC)
Power dissipation – 700mW
Simultaneous outputs – sine wave
Square wave and Triangle
Low distortion – 1%
High linearity – 01%
8038
Easy to use – 50% reduction in external
components
Wide frequency range of operation 0.001
Hz to 1.0Mhz
Variable duty cycle – 2% to 98%
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Supply voltage - ±18V or 36V total
Power dissipation – 750mW
Input voltage (any pin) Not to exceed
supply voltages
Input current (pins 4 and 5 ) – 25mA
Operating temperature range: 55oC to
+125oC
Supply Voltage ±22V
Power Dissipation 500mW
Differential input voltage ±30V
µA741
Input voltage ±15V
Operating Temperature -55o to +125oC
Storage
Temperature
range
-55o
to
+150oC
Supply Voltage ±18V
Power Dissipation 680mW
Input voltage ±15V
TL084
Operating Temperature -0o to +70oC
Storage
Temperature
range
-65o
to
+150oC
Operating tem :SE 555 -55oC to 125oC
NE 555 0o to 70oC
IC 555
Supply voltage
:+5V to +18V
Timing
:µSec to Hours
Sink current
:200mA
Temperature stability :50 PPM/oC change
in temp or 0-005% /oC.
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REFERENCES:
•
Digital Communications - by John Proakis, TMH
• Communication Systems - by Simon Hay kin, John Wiley
• Communication Systems –by Sanjay Sharma
• Digital Communication Fundamentals & Applications –by
Bernard Sklar
• Principles of Digital Communications – by P.Chakrabarthi
•
Theory and Design of Digital communication Systems
–by Tri T HA
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