What is VSB Modulation : Working and Its Applications

In the field of communication, the most frequently used modulations are SSB as well as DSBSC. If the carrier is covered up & the saved power is dispersed to the two sidebands, so this is called DSBSC or double sideband suppressed carrier system. The suppressing process of one of the sidebands using the carrier as well as transmitting an only sideband is named as SSB or SSBSC (single sideband suppressed carrier system). In SSB, whenever a sideband is moved throughout the filters, then the filter like bandpass cannot work completely in practice so some of the data may get lost. However, in DSBSC, two sidebands are transmitted to carry the waste data. Therefore to overcome this failure, a method is chosen called VSB modulation and it includes between DSBSC and SSB. The term “vestige” means apart from the derived name.

What is VSB Modulation?

The term VSB stands for vestigial sideband; it is a kind of amplitude modulation technique, where a part of the signal named as a vestige and it is modulated with one sideband.


For the transmission, both the bands are not necessary, because it is a waste. But if a single band is transmitted, then the data will be lost. Therefore, this method has developed. A VSB signal is designed like the following image.

vsb-modulation
VSB-modulation

In conjunction with the higher sideband, a fraction of the lesser sideband is also being broadcasted in this method.

An extremely small size protector band is laid on any side of vestigial sideband for avoiding the intrusions. This modulation is frequently used in TV transmissions. The VSB modulated wave’s transmission BW will be the sum of message bandwidth & the size of VSB.

Advantages

The advantages of VSB modulation include the following.

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  • The main benefit of this modulation is the decrease in BW. It is approximately efficient like SSB
  • High efficient
  • Designing of the filter is simple when high accuracy is not necessary.
  • Because of the transmitting allowance of a lower sideband part, the filter constraints will be relaxed.
  • It makes possible for the low-frequency components transmission as well as good phase characteristics without trouble.
  • For incomplete LSB suppression, practical filters are utilized.

Disadvantages

The disadvantages of VSB modulation include the following.

VSB Modulation Applications

The applications of VSB modulation include the following.

  • VSB modulation is standard for the transmission of TV signals. Because the video signals require a large transmission BW using the techniques like DSB-FC otherwise DSF-SC.
  • This is a type amplitude modulation that is mainly used for the TV broadcast worldwide. In this broadcast, it is essential to broadcast the information of video and audio concurrently.
  • In the transmission of VSB, the higher sideband of video signal & picture carrier are broadcasted without any control. Where a vestige is a fraction of lower sideband and it is transmitted & the residual part is covered up
  • When the usage of BW is considered, then this is the most suitable and proficient technique.

Thus, this is all about VSB modulation. The most important and typical application of this modulation is for the broadcast of TV signals. Here is a question for you, what is the meaning of vestige?

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