Q. Consider the following statements as regards pulse repetition frequency

1. Pulse interval should be as large as possible so that a pulse returns before next pulse is transmitted
2. Greater the number of pulses reflected from a target, greater is the probability of distinguishing it from the noise

Which of the above are correct?

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Q. Which gives minimum probability of error?

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Q. If there are M messages and each message has probability p = 1/m, the entropy is

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Q. Narrowband FM signal can be considered to be equal to

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Q. The spectral component of noise associated with kth frequency is given, in the limit as Δf → 0 by nk(t) written as

nk(t) = Ck cos (2πk Δft + θk)

Consider the following statements as regards Ck and θk

1. Ck and θk are independent of one another
2. Ck and θk are independent of the amplitude of a spectral component at a different frequency
3. Ct and θk are independent of the phase of a spectral component at a different frequency

Which of the above statements are correct?

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Q. A narrowband amplifier is one that has a passband

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Q. In pulse code modulation, if the signal is sampled at the rate of f and the number of pulses in one code group is p, then the number of pulses per second will be

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Q. A narrow band FM does not have the following feature

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Q. When number of quantization levels are two, then the average transmission power in NRZ polar signalling is __________ that of NIRZ unipolar signalling.

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Q. In telecast

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Q. A pulse width signal can be governed by

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Q. Which SNR denotes excellent picture quality in TV?

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Q. In amplitude modulation

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Q. At f = 7 GHz, a 120 cm dish antenna gives a gain of about

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Q. PIL colour picture tube has the main advantage that

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Q. What is the frequency of the modulated carrier wave?

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Q. In high power AM transmission, modulation is done at

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Q. The noise sources shot noise, partition noise and thermal noise are associated with which component

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Q. Consider the following statements as regards communication receiver

1. Variable sensitivity is used to eliminate selective fading
2. A product demodulator can be used to receive Morse code
3. The noise limiter cuts off receiver output during a noise pulse
4. Double conversion is used to improve image rejection

Which of the above statements are correct?

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Q. In a transmission line, losses due to dielectric heating are

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