Ques.1. 1. An odd and imaginary signal always has an odd and real Fourier transform.
2. The convolution of an odd Fourier transform with an even Fourier transform is always even.
Which of the above statements is/are true:
- 1 & 2
- 1 only
- 2 only
- None of the above
2. In a communication system noise is most likely to affect the signal
- At the transmitter
- In the channel
- At the receiver
- Both 2 and 3
3. In a modulation system, if the modulating frequency is doubled, the modulation index also becomes double, the system is
4. When the modulating frequency is doubled, the modulation index is halved and the modulating voltage remains constant, the modulation system is
5. If two tones f1 and f2 are amplified by a non-linear amplifier, which frequency components would be present in output?
- f1, f2
- f1, f2, f1 + f2, f1 – f2
- f1 + f2, f1 – f2
- nf1 ± mf2, where n and m are integers
6. Consider the following types of modulation:
1. Amplitude modulation
2. Frequency modulation
3. Phase modulation
4. Pulse modulation
Which of the above modulation are used for telecasting TV programs?
- 2 and 3
- 3 and 4
- 1 and 2
- 1 and 4
7. Calculate the modulation percentage if the modulating signal is 8 V and carrier is of 12 V?
8. Which of the following devices is used for modulation & demodulation?
9. Which one of the following is not a positive communication vehicle?
10. Radio channel used for transmission of information from the base station to the mobile is called: