ANALOG COMMUNICATION

1. Define modulation?

            Modulation is a process by which some characteristics of high frequency carrier signal is varied in accordance with the instantaneous value of the modulating signal

2. Define depth of modulation.

            It is defined as the ratio between message amplitude to that of carrier amplitude.

3. What is the need of modulation?

            -Ease of transmission

            -multiplexing

            -reduce noise

            -narrow bandwidth

            -reduce the equipments limitations

4. What is the degree of modulation?

            -Under modulation, m<1

            -Critical Modulation, m=1

            -Over modulation, m>1

5. What are the two types of modulator?

            -linear modulator

            -Non-Linear modulator

6. What are the advantages of VSB-AM?

            -It has bandwidth greater than SSB but less than DSB system.

            -Power transmission greater than DSB but less than SSB system

            -No low frequency component loss. Hence it avoids phase distortion

7.How will you generating DSBSC-AM?

                        There are two ways of generating DSBSC-AM such as,

            -Balanced modulator

            -Ring Modulator

8. Define frequency modulation.

            Frequency Modulation is a process by which frequency of carrier signal is varied in accordance with the instantaneous value of the modulating signal.

9. Define modulation index of frequency modulation.

            It is defined as the ratio of maximum frequency deviation to the modulating frequency.

10. State the Carson’s rule.

            An approximate rule for the transmission bandwidth of an FM signal generated by a single tone modulating signal of frequency.