ECE :: Communication Systems
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In telephone systems the relation between load r, number of calls initiated during a specified interval λ and average duration of a call (h) is
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In a Vidicon camera tube
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In a CD the sampling frequency is nearly
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Consider the following statements about loop antenna
- It is suitable for direction finding application
- It is a single turn or multiturn coil carrying RF current
- The loop is surrounded by a magnetic field everywhere perpendicular to the loop
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Which of the following is present in both TRF receiver and superheterodyne receiver?
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When the carrier is unmodulated, a certain transmitter radiates 9 kW when the carrier is sinusoidally modulated the transmitter radiates 10.125 kW. The modulation index will be
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A signal x(t) = 100 cos (24p x 103t) is ideally sampled with a sampling period of 50 μ sec and then passed through an ideal low pass filter with cut off frequency of 15 kHz Which of the following frequencies are present at the filter output?
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A sinusoidal voltage of 2 kV peak value is amplitude modulated to give 20% modulation. The peak value of each side band term is
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Consider the following reasons for using antenna coupler
- To prevent illegal radiation of spurious frequencies
- To tune out reactive components of antenna impedance
- To have correct value of load impedance for transmitter.
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12 kHz, 8 kHz.
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