*Question E2B05:
Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?*  

*Correct Answer is  C: Vestigial sideband reduces the bandwidth while increasing the fidelity of low frequency video components*  

### AI Response: (may contain errors)  

Vestigial sideband (VSB) is a technique used in analog fast-scan TV transmissions to efficiently transmit video signals. Here's why the correct answer is correct and why the other choices are incorrect:

1. **Correct Answer: C**  
   Vestigial sideband reduces the bandwidth while increasing the fidelity of low frequency video components.  
   - **Explanation**: In analog TV, the video signal is amplitude modulated. A full double sideband transmission would require a lot of bandwidth. By using vestigial sideband, one of the sidebands is partially suppressed, which reduces the overall bandwidth required. This allows for more efficient use of the spectrum while maintaining the quality of the low-frequency components of the video signal, which are crucial for picture detail.

2. **Why the Other Choices are Incorrect**:
   - **Choice A**: The vestigial sideband carries the audio information  
     - **Explanation**: Audio information in analog TV is typically transmitted using frequency modulation (FM) on a separate carrier, not within the vestigial sideband.
   
   - **Choice B**: The vestigial sideband contains chroma information  
     - **Explanation**: Chroma (color) information is typically transmitted using a separate subcarrier within the video signal, not specifically within the vestigial sideband.
   
   - **Choice D**: Vestigial sideband provides high frequency emphasis to sharpen the picture  
     - **Explanation**: The purpose of the vestigial sideband is not to emphasize high frequencies but to efficiently transmit the necessary video information while reducing bandwidth. High frequency emphasis is typically achieved through other means, such as pre-emphasis techniques.

In summary, vestigial sideband modulation is a compromise that allows for reduced bandwidth usage while preserving the essential low-frequency components of the video signal, which are important for maintaining picture quality.