Question

Explain briefly the following terms used in communication system:
(a) modulation; and (b) transducer.

Answer 1

(a) Modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.

In amplitude modulation, amplitude of high frequency carrier wave is varied in accordance with some characteristic of the modulating signal.

In frequency modulation, frequency of high frequency carrier wave is varied in accordance with instantaneous frequency of the modulating signal.

(b) A transducer is a device which is capable of converting the physical quantity into a proportional electrical quantity such as voltage or electric current. Hence it converts any quantity to be measured into usable electrical signal. This physical quantity which is to be measured can be pressure, level, temperature, displacement etc. The output which is obtained from the transducer is in the electrical form and is equivalent to the measured quantity.