Q161
Open questionThe bandwidth of the spectrum over which the hopping occurs is called
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Communication Systems
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Q162
Open questionAM signal represented as
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Q163
Open questionAn FM wave is represented by y(t) = 10sin[2000πt + 4sin1250πt]. The maximum frequency deviation is:
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Q164
Open questionThe amplitude modulated wave form s(t) = AC[1 + Kam(t)]cosωCt is used an ideal envelope detector. The maximum magnitude of Kam(t) is greater than 1. Which of the following could be the detector output?
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Q165
Open questionIn an amplitude modulated system if the total power is 600 W and the power in the carrier is 400 W, the modulation index is
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Q166
Open questionAn AM broadcast station operates at its maximum allowed total of 100 kW with 90% modulation. The power in the intelligence part is
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Q167
Open questionA signal m(t) = 10cos 2π100t is frequency modulated. The resulting FM signal is x(t) = 20cos{2π106t + 15sin(2π100t)}. The FM bandwidth is nearly
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Q168
Open questionA frequency modulated signal can be demodulated by-
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Q169
Open questionWhich of the following is NOT the advantage of frequency modulation?
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Q170
Open questionNoise figure of an amplifier depends on
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Q171
Open questionA frequency multiplier circuit
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Q172
Open questionA carrier is simultaneously modulated by two sine waves with modulation indices of 0.3 and 0.4. The total modulation index will be-
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Q173
Open questionA circuit produces an output y(t) = a + bx2(t) where x(t) is its input. This circuit can produce which one of the following?
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Q174
Open questionThe signal m(t) = sinc (2 × 104t) is frequency modulated with K = 103 Hz/V. What is the maximum instantaneous frequency of the modulated signal when carrier frequency is 1 MHz?
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Q175
Open questionLet m(t) denote a message signal and denote the Hilbert transform of m(t). Let the carrier frequency by ωc. Then, the single sideband (SSB) modulated signal with the upper sideband (USB) transmitted is given as
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Q176
Open questionIf the variance of d(n) = x(n) - x(n - 1) is one-tenth the variance of a stationary zero-mean discrete-time signal x(n), then the normalized autocorrelation function at K = 1 is
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Q177
Open questionAn arbitrary signal m(t) has zero average value and it is band-limited to 3.2 kHz. It is sampled at the rate of 8 k samples/s. The samples are passed through an ideal band-pass filter with centre frequency of 32 kHz and bandwidth of 6.4 kHz. The output of the band-pass filter is
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Q178
Open questionIn a low-level AM system, the amplifier which follow the modulated stage must be the
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Q179
Open questionIf X is a zero mean Gaussian random variable, then P(X ≤ 0) is
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Q180
Open questionTotal bandwidth needed for an AM signal at 55.25 MHz with 0.5 MHz video modulation is
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