Previous year question paper for CS (Diploma Electronics and Communication Engineering 4th)

Communication Systems

Previous year question paper with solutions for Communication Systems from 2014 to 2018

Our website provides solved previous year question paper for Communication Systems from 2014 to 2018. Doing preparation from the previous year question paper helps you to get good marks in exams. From our CS question paper bank, students can download solved previous year question paper. The solutions to these previous year question paper are very easy to understand.

1. AM/FM Transmitters (04 hrs)

a) Classification of transmitters on the basis of modulation, service, frequency and power

b) Block diagram of AM transmitters and working of each stage

c) Block diagram and working principles of reactance FET and armstrong FM transmitters

2. AM/FM Radio Receivers (10 hrs)

a) Principle and working with block diagram of super heterodyne AM receiver. Function of

each block and typical waveforms at input and output of each block

b) Performance characteristics of a radio receiver: sensitivity, selectivity, fidelity, S/N ratio,

image rejection ratio and their measurement procedure. ISI standards on radio receivers

(brief Idea)

c) Selection criteria for intermediate frequency (IF). Concepts of simple and delayed AGC

d) Block diagram of an FM receiver, function of each block and waveforms at input and output

of different blocks. Need for limiting and de-emphasis in FM reception

e) Block diagram of communication receivers, differences with respect to broadcast receivers.

3. Antennas: (12 hrs)

a) Electromagnetic spectrum and its various ranges: VLF, LF, MF, HF, VHF, UHF,


b) Physical concept of radiation of electromagnetic energy from a dipole. Concept of

polarization of EM Waves.

c) Definition and physical concepts of the terms used with antennas like point source, gain

directivity, aperture, effective area, radiation pattern, beam width and radiation resistance,

loss resistance.

d) Types of antennas-brief description, characteristics and typical applications of half wave

dipole, medium wave (mast) antenna, folded dipole, patch, loop antenna, yagi and ferrite

rod antenna (used in transistor receivers)

e) Brief description of broad-side and end fire arrays, their radiation pattern and applications

(without analysis); brief idea about Rhombic antenna and dish antenna


4. Propagation: (12 hrs)

a) Basic idea about different modes of wave propagation and typical areas of application.

Ground wave propagation and its characteristics, summer field equation for field strength.

b) Space wave communication – line of sight propagation, standard atmosphere, concept of

effective earth radius range of space wave propagation standard atmosphere

c) Duct propagation: sky wave propagation - ionosphere and its layers. Explanation of terms - virtual height, critical frequency, skips distance, maximum usable frequency, multiple hop


5. Digital Modulation Techniques (10 hrs)

Introduction of:


b) DELTA Modulation

c) Basic block diagram and principle of working of the following ASK, FSK, PSK, QPSK

d) Spread Spectrum Techniques, Frequency Hopping Technique