Mumbai University > Electronics Engineering > Sem4 > Fundamentals of Communication Engineering

Marks: 5M

Year: May2014

SSB is an amplitude modulation technique in which only one sideband (upper or lower) is transmitted and DSB is a modulation technique in which both the upper and lower sidebands are transmitted.

• Advantages of SSB over full carrier DSB wave

1. The bandwidth requirement of the single sideband system is half than required by double sideband system.
2. Since SSB system utilizes half the bandwidth than DSB, the thermal noise power is reduced to half that of DSB system.
3. The full carrier DSB wave has poor efficiency since the major transmitted power is concentrated in the carrier which contains no information. Thus the total power in SSB is less than the total power in DSB. % power saving in SSB is 83.33%.
4. In the spectrum of AM wave, both the sidebands carry same amount of information which makes it meaningless to transmit same information in both the sidebands thus leading to power wastage. This is overcome in the SSB technique by suppressing undesired sideband.

• Disadvantages of SSB over full carrier DSB wave

1. The generation of SSB is quite complex as the suppression of one of the sidebands is difficult.
2. The generation of SSB requires sharp cut off characteristics of the sideband suppression filter.
3. SSB receivers require more precise tuning than DSB
4. SSB receivers require carrier recovery and synchronization circuit which adds to their cost, complexity and size.