Q. Consider the following reasons for using antenna coupler

1. To prevent illegal radiation of spurious frequencies
2. To tune out reactive components of antenna impedance
3. To have correct value of load impedance for transmitter

Which of the above are correct?

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Q. Which of the following microphones works on the principle of Faraday's law?

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Q. In a CE amplifier connection, the emitter is at ground potential for

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Q. In an AM wave with m = 1, the carrier is suppressed. The resulting power saving will be

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Q. Directive gain is

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Q. Which of the following sampling frequencies is considered adequate in voice telephony?

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Q. In telephone systems the relation between load ρ, number of calls initiated during a specified interval λ and average duration of a call (h) is

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Q. In a Vidicon camera tube

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Q. In a CD the sampling frequency is nearly

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Q. Consider the following statements about loop antenna

1. It is suitable for direction finding application
2. It is a single turn or multiturn coil carrying RF current
3. The loop is surrounded by a magnetic field everywhere perpendicular to the loop

Which of the above statements are correct?

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Q. Which of the following is present in both TRF receiver and superheterodyne receiver?

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Q. Which camera tube has highest dark current?

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Q. If a sound wave has a frequency of 50 Hz, the wavelength is

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Q. Skin depth at 1000 MHz in comparison with that at 500 MHz is

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Q. Consider the following

1. Generation of SSB signals
2. Design of minimum phase type filters
3. Representation of band pass signals

Which of the above applications is Hilbert transform used?

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Q. The dc voltage on plate modulated class C amplifier is 8 kV. If the peak modulating voltage is 4 kV, the peak RF voltage delivered to load is

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Q. The minimum step size required for a Delta modulator operating at 36 samples/sec to track the signal (here u(t) is the unit step function) x(t) = 125t (u(t) - u(t - 1)) + (250 - 125t) (u(t - 1) - u(t - 2)) So that slope overload is avoided, would be

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Q. An FM signal with a deviation δ is passed through a mixer, and has its frequency reduced 5 fold. The deviation in the output of the mixer is

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Q. In PCM, if the number of quantization levels is increased from 4 to 64, then the bandwidth requirement will approximately be increased __________ times.

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Q. A tweeter should be fed from the input through a

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