21. In a superheterodyne receiver, rejection of the image signal can be achieved by using a
22. In Amplitude Modulation, . . . . . . . . of total transmitted power is used for carrying message signal under best conditions.
23. Consider the following:
1. Filter system
2. Phase-shift method
3. Third method
4. Balanced modulator
Which of these can be used to remove unwanted side-bands in SSB?
1. Filter system
2. Phase-shift method
3. Third method
4. Balanced modulator
Which of these can be used to remove unwanted side-bands in SSB?
24. x(t) = A cosωt + B sinωt, the BW of A cosωt is 10 kHz, BW of B sinωt is 15 kHz the BW of the signal x(t) is . . . . . . . .
25. Which of the following is angle modulation
26. The diagonal clipping in Amplitude Demodulation (using envelope detector) can be avoided if RC time-constant of the envelope detector satisfies the following condition, (here W is message bandwidth and ω is carrier frequency both in rad/sec)
27. An antenna pointing in a certain direction has a noise temperature of 50 K. The ambient temperature is 290 K. The antenna is connected to a pre-amplifier that has a noise figure of 2 dB and an available gain of 40 dB over an effective bandwidth of 12 MHz. The effective input noise temperature Te for the amplifier and the noise power Pa0 at the output of the preamplifier, respectively, are
28. As the modulation index of an FM signal with sinusoidal modulation is increased from zero to three, the power in the carrier component will
29. In an amplitude modulated system, if the total power is 600 W and the power in carrier is 400 W, then the modulation index is
30. For an angle modulated signal x(t) = 3cos[2π106t + 2sin(2π103t)], what is the maximum frequency deviation?
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