ECE :: Communication Systems
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Which of the following microphones has bidirectional feature?
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In TV transmitter some possible advantages of IF modulation are
- The modulator section and visual exciter can be solid state devices
- VSB filter can be introduced at low power level
- The subsequent stages following VSB filter can be tuned permanently for wideband linear operation
- It is economical
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A source is radiating power equally in all directions. If source power is P, the power density at distance d is
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As compared to AM, FM requires
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The spectral component of noise associated with kth frequency is given, in the limit as Δf → 0 by nk(t) written as nk(t) = Ck cos (2pk Δft + θk)
Consider the following statements as regards Ck and θk- Ck and θk are independent of one another
- Ck and θk are independent of the amplitude of a spectral component at a different frequency
- Ct and θk are independent of the phase of a spectral component at a different frequency
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The power density spectrum of noise voltage at the input of a network is Sni and that at the output of the network is Sno. If transfer function of network is H(ω), the corresponding noise figure is
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A narrowband amplifier is one that has a passband
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In a modulator it is found that the amplitude spectrum consists a component at fc, the carrier frequency and one component each at fc - fs and fc + fs where fs is the modulating signal frequency. Then the modulator used is