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Communications

Communications for GATE Electronics and Communication Engineering, one topic per lesson: the theory in plain words, the formulas, a solved example, and GATE-style questions (MCQ, MSQ and NAT) whose numerical answers are recomputed by a program when the site is built.

Start the first lesson

1Foundations

  1. Random Processes and NoiseRandom variables and processes, mean and autocorrelation, stationarity and ergodicity, power spectral density, white noise through LTI systems, thermal noise, noise figure and noise temperature.

2Analog Modulation

  1. Amplitude Modulation: AM, DSB-SC and SSBConventional AM, modulation index, power and efficiency, envelope detection, DSB-SC and coherent detection, SSB and VSB, superheterodyne receivers and image frequency.
  2. Frequency and Phase ModulationFM and PM signals, frequency deviation and modulation index, narrowband and wideband FM, Bessel spectrum, Carson's rule, generation and detection, pre-emphasis, and noise performance.

3Digital Communication

  1. Sampling, PCM and Digital ModulationSampling and quantisation, PCM bit rate and SQNR, delta modulation, line coding, ISI and Nyquist pulse shaping, ASK, FSK, PSK and QAM, matched filter and bit error probability.

4Information Theory

  1. Information Theory and CodingInformation and entropy, source coding with Huffman and Shannon-Fano, coding efficiency, mutual information, channel capacity of binary symmetric and AWGN channels, and linear block codes.