Write definitions.
(i) Transducer
(ii) Modulation

Hint:Recall the basics of the digital communication system. Recall the basic processes and devices used in the digital communication system. Go through the concepts of transducer and modulation in the digital communication system and write definitions of these terms.

Complete step by step answer:
(i) The device which is used to convert a physical quantity into an equivalent electrical signal as its output is known as a transducer.
(ii) The process in which the properties of a carrier signal that carries the information to be transmitted are changed with a modulating signal is known as modulation.

Additional information:
The transducers convert one form of energy into another form of energy. The inputs to the transducer are the physical variables such as displacement, pressure, force, temperature, etc which are converted into electrical signals as their outputs.The modulation process can also be defined as the process in which there is superimposition of a low frequency signal on a high frequency signal and for transmission over long distances this signal behaves like a carrier wave is known as modulation.The modulation is of three types which are amplitude modulation, frequency modulation and phase modulation.The process in which there is a variation in the amplitude of the carrier wave with high frequency considering the properties of the modulating signal is known as the amplitude modulation.The process in which there is a variation in the frequency of the carrier wave with high frequency considering the instantaneous frequency of the modulating signal is known as the frequency modulation.The process in which there is a variation in the phase of the carrier wave with high frequency considering the instantaneous phase of the modulating signal is known as the phase modulation.

Note:There are various definitions available for the terms transducer and modulation. The students may get confused between the various definitions of these two terms. One of the standard definitions is provided in the solution.