Q. A helical antenna is used for satellite tracking due to its

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Q. The main advantage of superheterodyne receiver is

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Q. PAL system was proposed first in

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Q. MCVF telegraphy causes

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Q. Consider the following statements as regards noise

1. If Gaussian noise is applied at input of a rectifier, the output is not gaussian
2. The noise encountered on a telephone line consists of short, pulse type disturbances whose amplitude distribution is not Gaussian
3. Shot noise results from random emission of electrons from a cathode
4. Shot noise results from phenomenon associated with the flow of current across semi conductor junctions

Which of the above are correct?

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Q. Noise can be reduced by increasing sampling rate

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Q. Which of the following is invariably found in SSB?

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Q. In the spectrum of a frequency modulated wave

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Q. Which of the following pulse communication system is inherently immune to noise?

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Q. In a PCM system, if we increase the quantization levels from 2 to 8, how do the relative bandwidth requirements vary?

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Q. If the target area is small compared to wavelength of radar the situation is called

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Q. An FM transmitter has maximum frequency deviation of 75 kHz and reproduces audio signals up to 15 kHz. Minimum channel width required is __________ kHz.

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Q. A 360 W carrier is simultaneously modulated by two audio wave with modulation percentage of 55 and 65 respectively. Total sideband power radiated will be

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Q. In a radio detector

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Q. ISDN stands for

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Q. Under identical conditions, for a single modulating frequency, FM and PM are indistinguishable. Now if the modulating frequency is reduced, then

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Q. The percentage saving in power when the carrier and one of the sidebands are suppressed in an AM wave modulated to a depth of 100% will be nearly

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Q. The difference between phase and frequency modulation

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Q. A signal m(t) amplitude modulates a carrier Ac cos ωct. The final signal will be

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Q. An oscillator at 4.2 MHz is followed by two frequency doublers and two triplers. The output frequency will be

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