Digital Communication — Summer 2025

Draw and Explain the basic building blocks of Digital communication.

Define CDF. What are the important properties of CDF? State and prove them.

State and prove sampling theorem.

Explain T1 Carrier System.

Difference between DPCM and ADPCM.

Explain quantization in detail. Derive equation for quantization error.

Derive the expression of Power Spectral Density (PSD) of On-Off signaling technique. Sketch the PSD of On-Off signaling technique.

Define the terms Mean, Central moment and Variance of a Random Variable.

Explain chebyshev’s inequality.

Explain Scrambler and Descrambler in a detail with diagram.

What do you mean by line coding? Explain unipolar NRZ and Bipolar RZ.

Explain regenerative repeater in a detail with each sub-block.

State and Prove Central limit theorem with necessary equation and waveform.

Differentiate coherent and non-coherent detection technique in detail with explain.

Define and explain : (i) Noise Figure (ii) Noise temperature.

What is QAM ? State the merits of QAM. Among the following QAM scheme which has more probability of error for same signal to noise ration, explain with proper insight. 8-QAM, 16- QAM, 32-QAM and 64-QAM.

Draw the waveform for the given sequence 1 1 0 1 0 0 1 With following modulation technique : (i) ASK (ii) FSK (iii) PSK

With diagram explain the principle of BPSK.

Explain non-coherent detection of frequency-shift keying signal with necessary equations.

Explain Convolution code decoding process with examples.

Explain hamming bound condition with mathematical background.

Derive the Channel Capacity of Discrete Memory less Channel.1

Entropy is maximum for equiprobable messages. Justify the statement.

Derive the relationship between channel capacity and signal to noise ratio in the light of shannon's theorem.

For a (7,4) cyclic code using the generator polynomial g(x) = x3 + x + 1, (i) Construct the decoding table, (ii) If the received word is 1101100, determine the transmitted data word. ]