Answer / roz

bandwidth of signals used for picture reception is very
large,so standard am cannot be used.if ssb were used,it
would result in half the bandwidth.but,ssb receivers being
compllex,they are not used.so vestigial transmission is used
in which a vestige or trace of the unwanted sideband is
transmitted along with the wanted sideband and carrier.

Answer / rajesh

SSBSC modulation saves bandwidth because in the standard AM
wave carrier causes wastage. With SSBSC we transmit one side
band because the other side band is just a replica of
this.But, for Picture transmission which involves
significant low frequency components, SSB fails to create a
clear distinction of the side bands. One side band
transmitted often leaves out low frequency content which is
not negligible for picture transmission. In order to
overcome this, a vestige ( a trace ) of the other side band
close to the carrier frequency is transmitted in addition to
one of the side bands.

Hence, VSB is used for picture transmission

Answer / cheena jain

An amplitude modulated signal consists of three parts
1.modulating signal
2.lsb
3.usb
the information contained in both the bands is same
so to save power only one band is transmitted
but coz filters are used some information at the edges may
lost due to this a small part of lsb is transmitted (not
the whole)which acts as a guard band.

Answer / radhar

both side bands of a signal have same information.to reduce
the power wastage we are using vsb. for this we can use ssb
but the some portion of lsb have important information.

Answer / alan james

The video baseband signal used in TV in countries that use
NTSC or ATSC has a bandwidth of 6 MHz. To conserve
bandwidth, SSB would be desirable, but the video signal has
significant low frequency content (average brightness) and
has rectangular synchronising pulses. The engineering
compromise is vestigial sideband modulation. In vestigial
sideband the full upper sideband of bandwidth W2 = 4 MHz is
transmitted, but only W1 = 1.25 MHz of the lower sideband is
transmitted, along with a carrier. This effectively makes
the system AM at low modulation frequencies and SSB at high
modulation frequencies. The absence of the lower sideband
components at high frequencies must be compensated for, and
this is done by the RF and IF filters.

courtesy
http://en.wikipedia.org/wiki/Vestigial_side_band#Vestigial_sideband_.28VSB.29

Answer / deba

GENERALLY IN TRANSMISSION OF TV SIGNAL ,BY USING A
MODULATION REQUIRE LARGE BANDWIDTH OF 11MHZ, BUT USING VSB
WE REQUIRE LESS B.W OF 7MHZ.B.W IS DECREASED.

Answer / md akmal hussain

Vestigial Sideband Transmission is used for the transmission of Television signals.Because the video signals need a large transmission bandwidth if transmitted using DSB-FC or DSB-SC techniques.

Read more: http://wiki.answers.com/Q/Which_are_the_applications_of_vestigial_sideband#ixzz26540jFtu

Answer / abdul hamid

The video baseband signal used in TV in countries that use
NTSC or ATSC has a bandwidth of 6 MHz. To conserve
bandwidth, SSB would be desirable, but the video signal has
significant low frequency content (average brightness) and
has rectangular synchronising pulses. The engineering
compromise is vestigial sideband modulation. In vestigial
sideband the full upper sideband of bandwidth W2 = 4 MHz is
transmitted, but only W1 = 1.25 MHz of the lower sideband is
transmitted, along with a carrier. This effectively makes
the system AM at low modulation frequencies and SSB at high
modulation frequencies. The absence of the lower sideband
components at high frequencies must be compensated for, and
this is done by the RF and IF filters.

Answer / vijay

the usb & lsb are having some information.at the carrier
level it is difficult to separate both lsb,usb.so we use
vsb,in that lsb having information ,which is more suitable.

Answer / abdul hamid

In television VSB transmission system is used.A complete
upper side band and 1.25 lower side band along with carrier
is transmitted.The lower side band(1.25)is added with upper
side band to separate the two channels therefore the noise
is not interned in transmission.

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