B.TECH - Semester 6 digital communication Question Paper 2020 (jan)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Find the Nyquist sampling frequency to sample the following signals. (a) $g(\mathrm{t})=10 \sin (200 \pi \mathrm{t}) \cos (300 \pi \mathrm{t})$
- Find the Nyquist sampling frequency to sample the following signals. (b) $g(\mathrm{t})=10 \sin (200 \pi \mathrm{t})+20 \cos (300 \pi \mathrm{t})$
- Discuss aperture effect in flat-top sampling. How it can be avoided?.
- What is the need of regenerative repeater in a PCM system?
- Draw eye pattern? Define major parameters.
- Explain how continuous AWGN channel is converted to a vector channel.
- Draw Analyzer and synthesizer.
- Discuss properties of PN sequences.
- What is coherence time and coherence bandwidth?
- What is raised cosine spectrum?
- Explain TDMA. ( $\mathbf{1 0} \boldsymbol{\times} \mathbf{2} \boldsymbol{=} \mathbf{2 0}$ Marks) P.T.O. PART- B Answer any one questions from each Module Module - I
- (a) Derive SNR of quantizer. ..... 10
- (b) Explain DPCM. Derive processing gain ..... 10
- (a) Discuss Delta modulation. Explain the distortions ..... 10
- (b) Discuss various line coding schemes using example bit stream 1101011. ..... 10 Module - II
- (a) Explain ISI with necessary diagrams and expressions. ..... 10
- (b) Discuss any two solutions for ISI. ..... 1014. (a) Explain duobinary encoder with necessary derivations and diagrams? Howerror is propagated in the system? Discuss solution for error propagation.10
- (b) Derive the impulse response of a matched filter. ..... 10 Module - III
- (a) Derive Gram Schmidt orthogonisation procedure ..... 10
- (b) Derive BER of BFSK ..... 10
- (a) Draw QPSK waveforms for input sequence 10110011. ..... 10
- (b) Compare different modulation schemes. ..... 10
- (a) Explain generation of PN sequences using shift registers. Give examples.
- (b) With necessary mathematical expressions, explain DS/BPSK system.
- (a) Explain diversity techniques.
- (b) Differentiate between slow and fast frequency hopping with MFSK modulation.