Electronic Communication — Winter 2018

What is noise? Explain thermal noise.

Explain Communication system with the help of block diagram

What is modulation? Explain the need of modulation.

Two resistors of 20 Kand 50 Kare at room temperature of 15 degree Celsius. for a given bandwidth of 10MHz, determine the thermal noise voltage generated by

two resistors in series

two resistors in parallel

Amixer circuit has a noise figure of 12 dB. It is preceded by an

amplifier that has an equivalent noise temperature of 200K and a power gain of 30 dB. Calculate the equivalent noise temperature of combination referred to amplifier input.

Explain the Superhetrodyne receiver with block diagram.

Explain envelop detector for AM demodulation.

What is AGC? Explain simple AGC and delayed AGC with proper graph.

Explain Adjacent channel selectivity and image frequency rejection.

Compare AM, FM and PM List all the properties of Fourier transform. State and prove time Shifting

property.

Find the Fourier transform of the signal:

Define Amplitude Modulation. Derive the expression for AM modulated wave.

Give difference between SSB and VSB. Explain filter method with necessary block diagram.

Explain parallel tuned circuit and derive equation for resonant frequency and Q-factor.

Explain Series tuned circuit and derive equation for resonant frequency and Q-factor.

Explain phase shift method of SSB generation with necessary block diagram.1