Q. In a two stage cascade amplifier, each stage has a gain of 10 dB and noise figure of 10 dB. The overall noise factor is

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Q. An AM signal and a narrowband FM signal with identical carriers, modulating signals and modulation index of 0.1 are added together. The resultant signal can be closely approximated by

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Q. The equation v(t) = A cos [ωct + φ(t)] where A and ωc are constant and φ(t) is a function of base signal represents

1. Phase modulation
2. Amplitude modulation
3. Angle modulation
4. Frequency modulation

Which of the above are true?

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Q. An FM signal with deviation δ is passed through mixer. Its frequency is reduced five fold. The deviation in output of mixer is

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Q. The total number of channels allotted for cellular telephone is

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Q. It is found that in a telephone system 60 subscribers initiate calls during a 30 minute interval and the total duration of all the calls is 100 minutes. The load is

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Q. E and H fields are perpendicular to each other.

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Q. Consider the following:

1. A TV receiver antenna should pick up the TV signal and develop maximum voltage from the available strength of signal
2. It should reject unwanted signals
3. It should not suffer from co-channel interference
4. It should have a very narrowband

The correct statements are

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Q. If transmission bandwidth is doubled in FM, SNR is

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Q. Directivity means

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Q. If the oscillator output is modulated by audio frequencies upto 10 kHz, the frequency range occupied by the side bands will be

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Q. The power to the portable unit of a cordless telephone is provided by

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Q. In a AM wave the carrier and one of the side bands is suppressed. If m = 0.5, the percentage saving in power is

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Q. Computer communication networks have

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Q. Assertion (A): A balun is an RF impedance matching transformer.

Reason (R): Sometimes a booster amplifier is used with a TV set.

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Q. In a TV, studio the function of vision switcher is to

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Q. Y signal has maximum percentage of

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Q. To ensure good transient response in audio systems the natural frequencies should be

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Q. Consider the following features of monochrome TV

1. Number of lines per picture - 625
2. Interlace ratio - 2 : 1
3. Aspect ratio - 4 : 3
4. Channel bandwidth - 8 MHz

As regards CCIR system B, which of the above are correct?

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Q. In the absence of noise, if C is channel capacity in bits/s, δf is channel bandwidth in Hz and N is number of coding levels. Then

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