Deemed University 2009 A.M.I.E.T.E Electronics

(ii) If we want to reproduce 1 hour of this waveform how many sample values need to be stored? (5)

Q.3 a. What is PCM as applied to baseband transmission? With a neat illustration, briefly define the essential features of binary PCM. (7)

b. What is delta modulation technique? Comment on the motivation for this technique. (4)

c. A one-step linear predictive filter is to be used to sample a constant amplitude sinusoid. The ratio of sample frequency to sinusoid frequency is 10. Determine the prediction coefficient of the filter. (5)


Q.4 a. "Power is not a useful way to characterize a digital waveform" – Comment. Briefly define the likelihood ratio test. What is the meaning of the term "intersymbol interference"? (9)


b. What is band-pass modulation? Distinguish ranging from coherent detection and noncoherent detection. Mention the advantages and disadvantages of noncoherent detection. provide 2 examples for this kind of system. (7)


Q.5 a. What is FSK? With a neat block schematic define the implementation for noncoherent FSK detection that uses bandpass filters and envelope detectors. (9)

b. provide a brief fault performance analysis for coherently detected binary orthogonal FSK. (7)

Q.6 a. What is the feature of forward fault correction kind of fault control? How are fault correcting codes classified? Write a brief note on linear block codes. (7)

b. Using the generator polynomial , generate a systematic codeword from the (7, 4) codeword set for the message vector m = 1011. (4)

c. Use a dividing (feedback shift register) circuit to divide by . obtain the quotient and remainder terms. (5)



Q.7 a. With a neat sketch for illustration, discuss the encoding of a cyclic code in systematic form, with an (n-k) – stage shift register. (8)


b. elaborate the features of Hamming codes, extended Golay code and BCH codes? (8)


Q.8 a. Fig.1 indicates a convolutional encoder (rate). Write the state diagram representation for the encoder and discuss. (9)


























b. elaborate the requirements to be fulfilled by a system to be called a spread-spectrum system? Write a brief note on pseudonoise sequences. (7)


Q.9 a. With neat schematics, discuss the direct sequence SSBPSK transmitter and receiver. (11)

b. A total of 24 equal-power terminals are to share a frequency band through a code division multiple access system. every terminal transmits info at 9.6 K bits/S with a DSS-BPSK modulated signal. compute the minimum chip rate of the PN code in order to maintain a bit fault probability of . presume that the receiver noise is negligible with respect to the interference from the other users. (5)

Earning:   Approval pending.