CBSE Class 12-science Answered

Detection or Demodulation is the process of retrieval of information from the modulated carrier wave at the receivers end . The device used for this purpose is called a detector or a demodulator.

The block diagram of an AM wave receiver has been shown in the figure above. As the received signal from receiving antenna is a weak one, the signal is amplified by the use of an amplifier. To facilitate further processing, the carrier frequency is usually changed to a lower frequency by the use of an intermediate frequency stage (IF). After this the carrier is supplied to the detector. As the detected signal may not be strong enough to be made use of, we again amplify the detected modulating (message) signal before converting it into proper voice or video format.