Analog Communication SSBSC Modulation - Analog Communication

What is SSBSC Modulation? How do you find out using mathematical expressions?

In the previous chapters, we have mentioned about DSBSC modulation and demodulation. The DSBSC modulated signal consists of two sidebands that is double sided band. The two side bands contains the same information, hence there is no need to transmit from both sidebands. One of the sideband can be eliminated.
SSBSC is a derivative of amplitude modulation. It is type of modulation used to transmit information suppressing one of the sidebands along with the carrier and transmits the information from a single sideband is called as Single Sideband Suppressed Carrier system or simply SSBSC. It is plotted as shown in the following figure.
Single Sideband Suppressed Carrier system
You can see in the above figure, the carrier and the lower sideband are suppressed. Hence, the upper sideband is used for transmission. Similarly, vise versa you can suppress the carrier and the upper sideband when the lower sideband is used for transmission.
This SSBSC system, which transmits a single sideband contains high power as compared to that of having power in both the sidebands because the power allotted for both the carrier and the other sideband is utilized in transmitting this Single Sideband.

Mathematical Expressions

Let us consider the same mathematical expressions for the modulating and the carrier signals as we have considered in the earlier chapters.
i.e., Modulating signal
modulating and the carrier signals
Mathematically, we can represent the equation of SSBSC wave as
SSBSC wave

Bandwidth of SSBSC Wave

We know that the DSBSC modulated wave contains two sidebands and its bandwidth is 2fm. Since the SSBSC modulated wave contains only one sideband, its bandwidth is calculated as half of the bandwidth of DSBSC modulated wave.
bandwidth of SSBSC modulated wave
Therefore, the bandwidth of SSBSC modulated wave is fmfm and it is equal to the frequency of the modulating signal.

Power Calculations of SSBSC Wave

Consider the following equation of SSBSC modulated wave.
Power Calculations of SSBSC Wave
Power of SSBSC Wave

Advantages

What are the advantages of SSBSC Modulation?

  • Less Bandwidth or spectrum space is requires compare to that of AM and DSBSC waves.
  • Allowing transmission of more number of signals.
  • Less Power consumption.
  • Capacity to transmit high power signal.
  • Reduced interference of noise.
  • Signal fading is less likely to occur.

Disadvantages

  • The generation and detection of SSBSC wave is quite a complex process.
  • The signal quality gets affected if the SSB transmitter and receiver does not possess an excellent frequency stability.

Applications

  • Applied for power saving requirements and low bandwidth requirements.
  • In land, air, and maritime mobile communications.
  • In point-to-point communications.
  • In radio communications.
  • In television, telemetry, and radar communications.
  • In military communications, such as amateur radio, etc.

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