Q. Consider the following:

1. A signal f(t) and its Hilbert transform fh(t) have the same energy density spectrum
2. A signal f(t) and its Hilbert transform, fh(t) have the same auto correlation function
3. A signal f(t) and its Hilbert transform are mutually orthogonal

Which of the above are true?

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Q. Vidicon and plumbicon operate on the principle of

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Q. A TV receiver has a width of 60 cm. The aspect ratio is 4/3. The required EHT supply is about

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Q. The typical squelch circuit

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Q. Consider the draw backs

1. Slope overload
2. Serration noise
3. Granular noise

Which of these draw backs does Delta modulation have?

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Q. It is required to increase the maximum range of a radar by a factor of two. The peak power transmitted in the radar system has to be increased by a factor of

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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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