Demodulation

Demodulation

The process of extracting a modulating signal from a modulated signal is called demodulation or detection.

1        DSC-with carrier Demodulation

A demodulation process is just the opposition of a modulation process. An AM signal is a modulated signal that is high frequency carrier amplitude varied with low-frequency audio amplitude for transmission. To recover the audio signal in receiver, it is necessary to extract the audio signal from an AM signal.

2        DSC-SC Demodulation:

In double side band suppressed carrier demodulation high frequency carrier signal is suppressed at the receiver side and we have to generate the same carrier at the receiver side for the demodulation of the message signal.

3        VSB Demodulation:

In vestigial side band signal is easy to recover by a synchronous detector in conjunction with an appropriate equalizer filter at the receiver side. 

4        SSC Demodulation:

In single side band demodulation both the bands of double side bands upper side band and lower side band are not present one band is transmitted and phase shifting of carrier and Hilbert transform is used in this technique. 

5        QAM Demodulation

To recover the audio or message signals in receiver, it is necessary to extract the audio or message signals from modulated signal. We can demodulate two messages by multiplying the modulated signal with carrier and with the shifted version of the same carrier.