1. ECE4001 Digital Communication Systems L T P J C
3 0 2 0 4
Pre-requisite ECE3001 – Analog Communication Systems Syllabus version
1.1
Course Objectives:
1. To interpret the transmitter and receiver blocks of various waveform coding techniques.
2. To analyze various line coding techniques in time and frequency domains.
3. To identify the role of baseband and bandpass formats for effective transmission of signals,
combat ISI and to increase the reliability of transmission.
4. To understand the principles and importance of spread spectrum and multiple access in the
context of communication.
Course Outcomes:
1. Comprehend the sampling process of analog signal and recover the original signal without
any distortion.
2. Apply the knowledge of signal theory and evaluate the performance of various waveform
coding techniques.
3. Characterize various line coding techniques in time and frequency domains.
4. Design the baseband pulse for ISI free transmission over finite bandwidth channels.
5. Describe the mathematical model of a digital modulation technique, characterize the effect
of AWGN channel and determine its bit error rate performance.
6. Describe and analyze the digital communication system with spread spectrum modulation.
7. Design as well as conduct experiments, analyze and interpret the results to provide valid
conclusions for digital modulators and demodulators using hardware components and
MATLAB tool.
Student Learning Outcomes (SLO) 1,2,14
1. Having an ability to apply mathematics and science in engineering applications.
2. Having a clear understanding of the subject related concepts and of contemporary issues.
14. Having an ability to design and conduct experiments, as well as to analyze and interpret
data.
Module:1 Sampling and Quantization 4 hours
Model of digital communication system – Review of sampling – Quantization – Uniform & non-
uniform quantization.
Module:2 Waveform Coding Techniques 5 hours
Pulse Code Modulation (PCM) – Quantization noise and signal to quantization noise ratio –
Companding (A law and µ law) – Differential pulse code modulation-Delta modulation.
Module:3 Line Codes 6 hours
Representation of line codes – Properties and applications of line codes – Power spectral density
of NRZ unipolar, NRZ polar, NRZ bipolar and Manchester.
Module:4 Baseband System 7 hours
Inter Symbol Interference (ISI) – Nyquist criterion for distortion less transmission – Raised cosine
spectrum – Correlative coding – Eye pattern – Equalization.
Module:5 Bandpass System-I 8 hours
Gram-Schmidt orthogonalization procedure – Correlation receiver – QAM- Generation and
detection of coherent system (BASK, BFSK, BPSK, QPSK, MSK) – Error performance.

2. Module:6 Bandpass System-II 6 hours
Matched filter – Generation and detection of non-coherent system –DPSK, FSK and its error
performance.
Module:7 Spread Spectrum Techniques and Multiple Access Techniques 7 hours
Generation of PN sequence and its properties – Direct sequence spread spectrum – Processing
gain – Probability of error – Anti-jam characteristics – Frequency hopped spread spectrum – Slow
and fast frequency hopping – Multiple access techniques - TDMA, FDMA, CDMA
Module:8 Contemporary issues 2 hours
Total lecture hours: 45 hours
Text Book(s)
1. Simon Haykin, “Digital Communications”, 2014, 1st
edition, John Wiley, India.
Reference Books
1. John.G. Proakis, “Digital Communication”, 2014, 5th
edition, Pearson Education, Noida,
India.
2. Herbert Taub and Donald L Schilling,” Principles of Communication Systems”, 2012,
edition)”, Tata McGraw Hill, New Delhi.
3. Bernard Sklar, “Digital Communications: Fundamentals and Applications”, 2016, 2nd
edition,
Prentice Hall, New Jersey, US.
Mode of Evaluation: Internal Assessment (CAT, Quizzes, Digital Assignments) & Final
Assessment Test (FAT)
List of Challenging Experiments (Indicative)
SOFTWARE BASED TASKS
1 Simple digital communication system
Simulate a simple communication system which transmits a text
message from the source to the destination. Also, observe signals at
different points of this communication system.
2 hours
2 Coding for analog sources
Consider the given analog audio signal. Convert the analog input signal
into binary sequence using
i. Pulse code modulation (PCM)
ii. Differential pulse code modulation (DPCM)
iii. Delta Modulation (DM)
iv. Adaptive delta modulation (ADM)
Also, construct the stair-case approximated signal from the received
binary sequence using above mentioned decoding schemes.
In DM, analyse the impact of step size and sampling period on the stair
case reconstruction.
4 hours
3 Line coding
Write a code which uses the below mentioned line coding techniques to
generate the baseband signal for the given text message. Also, transmit
the generated base band signal through AWGN channel. Analyse the
effect of channel noise on the reconstructed signal.
i. Unipolar
ii. Polar
4 hours

3. iii. Bipolar
iv. Differential coding (Mark and Space)
4 Band-pass Modulation
Write a code which uses below mentioned band pass modulation
techniques to generate the modulated signal for the given text message.
Transmit the modulated signal through AWGN channel. Detect
transmitted message using the suitable rules. Plot the necessary graphs.
i. BASK
ii. BPSK
iii. BFSK
iv. DPSK
4 hours
5 Probability of error analysis
i. Consider the bit sequence of length 10,000. Modulate it with
BPSK, BASK, BFSK. Transmit the signal through AWGN
channel. Vary the SNR. Compare the theoretical and simulated
probability of error.
ii. Consider the bit sequence of length 10,000. Modulate it with
BPSK, QPSK and 8-PSK. Transmit the signal through AWGN
channel. Vary the SNR. Compare the theoretical and simulated
probability of error.
2 hours
6 Spread spectrum
Write a code to complete the following task:
i. For the given connection logic and the number of flip-flops,
generate the pseudo-noise (PN) sequence. Check whether the
given connection logic is primitive or not using periodicity
property.
ii. For the generated PN sequence, verify
a) Balance property
b) Run property
c) Auto-correlation property
iii. Use the generated PN sequence to get direct sequence spread
spectrum (DSSS) (Assume BPSK modulation). Construct a
simple transceiver chain.
iv. Use the generated PN sequence to get slow and fast frequency
hopped signals (Assume M-FSK modulation). Construct a
simple transceiver chain.
4 hours
Multiple Access
Consider 4 users with different data. Use the following multiple
access schemes to generate the composite signal. Use the
orthogonality property to get back the proper data at the receiver
end.
Multiple access schemes:
i. TDMA (Hint: Use GSM burst format)
ii. CDMA (Hint: Use Hadamard codes)
iii. OFDMA (Hint: Use IEEE 802.11a specifications)
4 hours
HARDWARE BASED TASKS
8 Generation and detection of ASK,FSK and PSK
Build the transceiver circuit for ASK,FSK and PSK scheme
2 hours
9 Implementation of QPSK modulation 2 hours

4. Build the transceiver chain for the QPSK scheme. Observe signals at
different points of communication system.
10 Adaptive linear Equalizer
Build the transceiver chain for adaptive linear equalizer and discuss the
RRC pulse generation and LMS rule.
2 hours
Total laboratory hours 30 hours
Mode of evaluation: Continuous assessment & FAT
Recommended by Board of Studies 28-02-2016
Approved by Academic Council No. 47 Date 05-10-2017