a) Explain and differentiate the following.
i) Linear and non linear system.
ii) Time invariant and time varying systems.
iii) Causal and non causal system. (Unit 1)

b) State and prove the following properties of Fourier Transform.
i) Time shifting
ii) Time Integration
iii) Convolution (Unit 1)

a) Find the Fourier transform of the function $x(t)=5t^{2}-15t$. How will be the Fourier transform be changed if this function has a period of 10 sec. (Unit 1)

b) What is modulation and what is the need of modulation in communication system explain in detail. (Unit 2)

A conventional AM transmitter station transmits with a modulation index of 0.9. the total power transmitted is 100kW. Find out the following
i) Power carries by the carrier.
ii) The faction of the total power carrying any message
iii) Does the total transmitted power is vary with the depth of modulation? Why?
iv) Calculate total transmitted power if the modulation is 100%. (Unit 2)

a) A 400Hz modulating signal of voltage 2.4 Volts is modulated under FM to have a modulation index of 60. Calculate the maximum deviation and required bandwidth. (Unit 3)

b) Explain the wideband FM transmission. What should be the value of modulation index for it to behave as Narrow band FM. (Unit 3)

a) Explain ratio detector method of detection of FM signals. Give its merits and demerits. (Unit 3)

b) Discuss the sampling and reconstruction of a low pass signal. (Unit 4)

a) With the help of block diagram explain the PCM communication system. (Unit 4)

b) Describe delta modulation system. What are its limitations? How can be overcome it. (Unit 4)

a) Explain the generation and receptions of BPSK system compare it with BFSK system. (Unit 5)

b) Discuss the generation and detection, spectrum and bandwidth of Amplitude Shift Keying. (Unit 5)

Write a short notes on any Two:

i) Ratio Detector (Unit 3)

ii) Superheterodyne receiver (Unit 2)

iii) TDM (Unit 4)

iv) QAM (Unit 5)