Write the function of (i) Transducer and (ii) Repeater in the context of communication system.

(i) Transducer: It is a device which converts one form of energy into another. It converts physical variable like pressure, displacement, force, temperature etc. into it's corresponding electrical signal at it's output. 

(ii) Repeater: A repeater is a combination of receiver and transmitter placed along the path of signal so as to extend the range of the communication system. Repeater picks up the signal from transmitter, amplifies it and re-transmits it to the receiver with a change in carrier frequency sometimes.