Introduction:
VSB (Vestigial Sideband) modulation is a widely used modulation technique in TV broadcasting. It has several advantages over other modulation techniques, making it the preferred choice for TV applications. One of the main advantages of VSB modulation is that it reduces the bandwidth requirement to half compared to other modulation techniques.

Explanation:
1. Bandwidth reduction:
VSB modulation is a form of amplitude modulation (AM) in which one of the sidebands is significantly attenuated or eliminated while the other sideband and the carrier are retained. This reduction or elimination of one of the sidebands allows for a significant reduction in the required bandwidth.

In TV broadcasting, the video signal occupies a wide frequency range, typically ranging from a few megahertz to several tens of megahertz. By using VSB modulation, the bandwidth requirement of the transmitted signal can be reduced to half of what would be required by other modulation techniques, such as double-sideband amplitude modulation (DSB-AM).

2. Avoidance of phase distortion at low frequencies:
Another advantage of VSB modulation is that it avoids phase distortion at low frequencies. In traditional AM modulation, the carrier and the two sidebands are transmitted simultaneously. However, in VSB modulation, one of the sidebands is either eliminated or significantly attenuated, resulting in a vestige of the other sideband.

This vestige sideband is typically centered around the carrier frequency and contains most of the information. By eliminating one sideband, the need for a phase shift at low frequencies is eliminated, reducing phase distortion and improving the overall quality of the transmitted signal.

3. Improved reception:
While VSB modulation does not directly result in better reception compared to other modulation techniques, the reduced bandwidth requirement allows for more efficient use of the available frequency spectrum. This means that more TV channels can be transmitted within the same frequency band, resulting in increased channel capacity and improved overall reception.

Conclusion:
In conclusion, VSB modulation is preferred in TV broadcasting due to its ability to reduce the bandwidth requirement to half compared to other modulation techniques. This reduction in bandwidth allows for more efficient use of the available frequency spectrum and increased channel capacity. Additionally, VSB modulation avoids phase distortion at low frequencies, resulting in improved signal quality.