Friday, 28 March 2014

VESTIGIAL SIDE BAND

Vestigial side-band (VSB) is a type of amplitude modulation (AM) technique (sometimes called VSB-AM) that encodes data by varying the amplitude of a single carrier frequency. Portions of one of the redundant side-bands are removed to form a vestigial side-band signal; so it is called Vestigial Wideband Modulation and the portion is called Vestige.
Instead of transmitting only one side-band as SSB, VSB modulation transmits a partially suppressed side-band and a vestige of the other side-band.
The following are the drawbacks of SSB signal generation:
1. Generation of an SSB signal is difficult.
2. Selective filtering is to be done to get the original signal back.
3. Phase shifter should be exactly tuned to 900.

To overcome these drawbacks, VSB modulation is used. It can be viewed as a compromise between SSB and DSB-SC.

No comments:

Post a Comment

Note: only a member of this blog may post a comment.