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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Q. The open loop gain of an amplifier is 50 but is likely to change by 20%. If negative feedback with β = 0.1 is used, the change in gain will be about

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Q. Audio amplifiers need

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Q. For an ideal 3000 Hz channel, S/N ratio is

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Q. Which of the following types of noise assumes greater importance at high frequencies?

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Q. In transistor radio receivers the number of IF amplifier stages are

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Q. To relay outdoor remotely located live programs, TV transmitter use

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Q. If each short element of signal occupies 20 ms, the speed is

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Q. The Hilbert transform of cos ω₁t + sin ω₂t is

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Q. In ionosphere incidence angle is 60°. The maximum usable frequency fm is equal to

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Q. The generally used value of EHV supply in TV receivers is

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Q. The number of channels available in MF band (300 kHz - 3 MHz) for AM modulating signal of 20 kHz is

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Q. The function of blend control in stereo system is

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Q. The output resistance of a microphone is 20 ohms. It is to feed a line of impedance 320 ohms. To ensure maximum power transfer, the turn ratio of transformer is

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Q. In a reactance FET, gm = 9 x 10‾³ Siemens, gate to source resistance is one-ninth of reactance of gate to drain capacitor and frequency is 4 MHz. The capacitive-reactance is

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