Q. Armstrong F.M. transmitter performs frequency multiplication in stages

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Q. A source generates three symbols with probabilities 0.25, 0.25, 0.50 at a rate of 3000 symbols per second. Assuming independent generation of symbols, the most efficient source encoder would have average bit rate is as

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Q. The filter circuit for feeding tweeter has

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Q. A narrow band noise n(t) has symmetrical spectrum and has power density spectrum 0.2 x 10‾⁶. The power density of quadrature component is

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Q. The radio receivers mostly used now a days are

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Q. The reactance of coupling capacitors, for DC quantities, is

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Q. An AM wave is given by s(t)AM = 20 (1 + 0.5 cos 10³t + 0.3 cos 10⁴ t cos 10⁶ t) the modulation index of the envelope is

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Q. The modulating frequency in frequency modulation is increased from 10 kHz to 30 kHz. The bandwidth is increased by

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Q. An AM signal is detected using an envelope detector, the carrier frequency and modulating signal frequency are 1 MHz and 2 kHz respectively. An appropriate value for the time constant of the envelope detector is

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Q. For signal amplitude modulated to a depth of 100% by a sinusoidal signal, power is

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Q. If transmitted power is 10 kW, the field strength at a distance d is 50 mV/m. If transmitted power is reduced to 2.5 kW, the field strength at the same point will be

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Q. Some features of advanced mobile phone service are

1. To provide telephone communication to a large number of telephone users within the area of a metropolitan only
2. To use minimum amount of frequency spectrum
3. To permit hand held as well as vehicle operation of telephone

Which of the above are true?

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Q. The carrier frequency will be if L = 50 µH and C = 1 nF.

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Q. Which of the following antennas is circularly polarized?

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Q. In colour TV system the colour sub carrier frequency is 4.43 MHz.

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Q. A transmitter power of 5 W is increased by 20 dB. The effective radiated power is

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Q. The percentage saving in power of 100% modulated suppressed carrier AM signal is

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Q. The maximum distance between television transmission and receiving antennas for reasonably good reception should be

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Q. Three point tracking is achieved with

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Q. In TV transmitter, visual exciter may consist of

1. Video processing unit
2. Visual modulator
3. VSB filter
4. Delay equaliser
5. Frequency converter

Which of the above are actually a part of visual exciter?

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