explain detection of am waves

CBSE Class 12-science Answered

explain detection of am waves

Asked by Indra | 25 Dec, 2014, 08:39: PM

Expert Answer

The amplitude modulation is the process in which the amplitude of the carrier varies in accordance with the changes in the amplitude of the modulating signal.

Detection of amplitude modulated wave:

The modulated signals are transmitted from the broadcasting stations. These signals are later received by the receivers. But the transmitted signal gets attenuated while passing through the channel. So, once the signal is received at the receiving antenna, it is passed through an amplifier. Then the carrier frequency is changed to lower frequency using an intermediate frequency (IF) stage and it is fed to the detector. The detected signal is again amplified.

The process of recovering the modulating signal from the modulated carrier wave is called detection. From the combination of

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, the original message signal of angular frequency

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is recovered by the detector.

The AM wave represented in fig. (1) is passed through the rectifier. The rectified output is received. The envelope of this output gives the message signal. This is passed through an envelope detector (RC circuit) and at the output the original message is recovered.

Answered by Faiza Lambe | 26 Dec, 2014, 10:19: AM