Printed Pages: 2
Paper Id 130507
Roll No.
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B. TECH
THEORY EXAMINATION (SEM-V) 2018-19
PRINCIPLES OF COMMUNICATION
REC502
Max. Marks: 70
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Note: Be precise in your answer. In case of numerical problem assume data wherever not provided
SECTION-A
- Attempt all parts of the following questions:
- (a) What is the function of limiter and frequency discriminator?
- (b) Define Modulation? List different types of AM.
- (c) Draw the waveforms of PAM, PPM and PWM.
- (d) Define Power Spectral Density? What is the PSD of AWGN?
- (e) What is noise? Discuss superposition of noise
- (f) What is line coding? Give its types?
- (g) Give Carson's rule? Find the bandwidth of Narrowband FM.
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2×7=14
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SECTION B
- Attempt any three parts of the following questions:
- (a) Derive the mathematical expression for single-tone FM. Determine the frequency deviation and carrier swing for a frequency-modulated (FM) signal which has a resting frequency of 105.00 MHz and whose upper frequency is 105.007 MHz when modulated by a particular wave. Find the lowest frequency reached by the FM wave.
- (b) What are the disadvantages of PAM and PWM signals? Discuss the generation of PPM signals using PWM signals. List the advantages of PPM.
- (c) Given that the bit sequence given below is to be transmitted
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Bit sequence 10110010
Draw the resulting waveform, if the sequence is transmitted using.
(i) Unipolar RZ
(ii) Polar RZ
(iii) AMI--- Content provided by FirstRanker.com ---
(iv) Split phase Manchester
(v) M-ary where m-4 (Polar Quaternary). - (d) A television signal having a bandwidth of 10.2 MHz is transmitted using binary PCM system. Given that the number of quantization levels is 512. Determine:
(1) Codeword length
(ii) Transmission bandwidth--- Content provided by FirstRanker.com ---
(iv) Final bit rate
(v) Output signal to quantization noise ratio. - (e) Define Figure of merit. Derive the mathematical expression of figure of merit for FM system.
3×7=21
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SECTION C
- Attempt any one part of the following question:
- (a) State and prove Sampling theorem. What is the criterion to remove Aliasing effect? Determine the Nyquist rate and Nyquist interval for a continuous-time signal x(t) = 6cos 50nt + 20 sin 300pt - 10 cos 100pe
- (b) Explain in detail Superheterodyne AM Receiver with labelled block diagram.
1×7=7
- Attempt any one part of the following question:
- (a) Explain the indirect method (Armstrong method) of generation of FM.
- (b) What is multiplexing? Explain TDM Hierarchy for digital communication in detail. List the advantages of digital multiplexing.
1×7=7
- Attempt any one part of the following question:
- (a) Explain the working of PLL-FM demodulator with supporting diagrams and mathematical expressions.
- (b) What is delta modulation? Discuss the errors in Delta Modulation. How they are overcome in Adaptive Delta Modulation?
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1×7=7
- Attempt any one part of the following question:
- (a) Define Figure of Merit. Derive an expression of figure of merit for AM system.
- (b) What are vocoders? List various types of vocoders and discuss them briefly.
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1×7=7
- Attempt any one part of the following question:
- (a) What is the need for modulation? List the differences between AM and FM.
- (b) Explain TRF receiver in detail. What are the drawbacks of TRF receivers?
1×7=7
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