Communication Systems - ECE Questions and Answers

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In TV system in India, each frame is divided into

625 horizontal lines

525 horizontal lines

425 horizontal lines

325 horizontal lines

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In PAL system

phase of U signal is reversed on alternating lines

phase of V signal is reversed on alternating lines

phases of both U and V signals are reversed on alternating lines

none of the above

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Among the various modulation systems, the most favoured from the point of linearity of modulation and efficiency is

anode or collector modulation

central grid modulation

screen grid modulation

modulated oscillators

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The phase of colour subcarrier burst in PAL is along the axis at

+180°

-180°

±180°

±45°

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Which of the following is correct (f_m is maximum usable frequency, S is speed and G is width of air gap)?

f_m = (S) (2G)

G = (f_m)(S)

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If the transmitted pulse power of a radar is P_t (peak value) and the antenna is isotropic, the power density at a distance r is

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In a hi-fi system the frequency response over the audio frequency range should be within

± 10 dB

5 dB

2 dB

1 dB

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Multiplex techniques are used for

low density communications

low density point-to-point communications

high-density point-to-point communications

all of the above

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In delta modulation, the output signal to quantization noise ratio S₀/N_q is (N is the number of bits)

N²

N³

N²

N³