B.TECH - Semester 6 digital communication Question Paper 2013 (apr)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- What is Nyquist criteria for zero ISI?
- Obtain the Nyquist rate and Nyquist interval of the signals : (a) $x(t)=\sin (200 t)$
- Obtain the Nyquist rate and Nyquist interval of the signals : (b) $x(t)=\sin ^{2}(200 \pi t)$.
- What are the advantages of Line codes?
- What are the advantages of correlative level coding?
- What is eye pattern?
- Obtain the geometrical representation of QPSK signal.
- Explain in DPSK.
- Write the properties of optimal receivers.
- How a pn sequence can be generated?
- What is frequency hopping? Answer any one full questions from each Module. Each question carries 20 marks.
- (a) With diagram explain the working of PCM modulator and demodulator. 10
- (b) Explain the working of a delta modulator transmitter. 10 OR
- (a) Prove that a sampled signal can be reconstructed by passing the samples through a LPF. 10
- (b) List merits and demerits of Delta Sigma modulation. Module - II
- (a) Explain the working of baseband M-ary PAM system.
- (b) List and compare the properties of Duobinary coding with that of Modified Duobinary coding. OR
- (a) What is a matched filter? Obtain the expression for impulse response of a matched filter.
- (b) Also find out the maximum signal to noise ratio. Module - III
- (a) Explain Gram Schmidt orthoganalization process.
- (b) Explain the working of BPSK system and derive the expression of probability of error of BPSK system. N-5895
- (a) Two functions $s 1(t)$ and $s 2(t)$ are given in figure (1)using Gram Schmidt orthoganalization process express these functions in terms of orthonormal functions. Fig. 1
- (b) Derive bit error probability of FSK.
- (a) Why RAKE receivers are used in CDMA? Explain with diagram.
- (b) Explain the importance of PN sequence in spread spectrum communication.
- (a) Explain how diversity techniques reduces fading?
- (b) A spread spectrum communication has the following parameters Information duration $=4.095 \mathrm{~ms}$ PN chip duration $=1 \mu \mathrm{~s}$ Calculate processing gain and jamming margin.