analog voice signal

analog voice signal

Telephone signals can be carried by radio using either analog or digital modulation schemes. Compare the bandwidth required to carry each of the following signals:
(a) an analog voice signal with a baseband bandwidth of 4 kHz using SSBSC AM (often used for terrestrial microwave links where many voice signals are transmitted together)
(b) the same analog voice signal using FM with a frequency deviation of 12 kHz (used for cellular phones)
(c) a standard digital voice signal using QPSK and assuming a channel with a signal-to-noise ratio of 20 dB. (Your answer to this question may suggest why data compression and vocoders are often used when digital signals are to be transmitted by radio.)

analog voice signal