1. Choose the correct answer from the following:

(a) Which of the following steps is not included in the process of reception Decoding
Encoding

(iii) Storage
Interpretation
What is the ratio of modulating power to total power at 100 percent modulation?
3
2

(iii) 3
None of the above Indicate the false statement regarding the Armstrong modulation system. The system is basically phase not frequency modulation.

(ii) AFC is not needed, as a crystal oscillator is used.

(iii) Frequency multiplication must be used.
Equalization is necessary. A low ratio of the ac to the dc load impedance of a diode detected results in Diagonal clipping

(ii) Poor AGC operation

(iii) -ve peak clipping
Poor AF response A pre-emphasis circuit provides extra noise immunity by Boosting the bass frequencies

(ii) Amplifying the higher audio frequencies

(iii) Pre-amplifying the whole audio band
Converting the phase modulation to FM Zoning is used with a dielectric antenna in order to Reduce the bulk of the lens

(ii) Increase the bandwidth of the lens

(iii) Permit pin-point focusing

(iv) Correct the curvature of the wavefront from a horn that is too short For transmission-line load matching over a range of frequencies, it is best to use a
Balun

(ii) Broadband directional coupler

(iii) Double stub

(iv) Single stub of adjustable position

2.(a) Define noise. What is it that is most likely to affect the signal Prove that the phase discriminator is an FM demodulator.

3.(a) Explain, with the-aid of waveforms, how a grid-modulated class C amplifier generates AM.

(b) List and discuss the factors influencing the choice of the intermediate frequency for a radio receiver.

4.(a) What is the function of the balanced modulator in the Armstrong modulation system? From the expression for the instantaneous voltage of an AM wave, derive a formula for the rms value of this wave.

5.(a) With suitable sketches, microwave antennas, performance. do a survey of comparing their

(b) Define the radiation resistance of an antenna. What is the significance of this quantity

6. What is refraction Explain under what circumstances it occurs and what causes it.

(b) Define the terms directivity and directional coupling as used with directional couplers, and explain their significance.

7. Write brief notes on the following: Space Wave Propagation Yagi-Uda Antenna

8.(a) Discuss the types of losses that may occur with RF transmission lines. In what units are these losses normally given Write about the Troposphere scatter propagation in brief.