*Question E2B06:
What is vestigial sideband modulation?*  

*Correct Answer is  A: Amplitude modulation in which one complete sideband and a portion of the other are transmitted*  

### AI Response: (may contain errors)  

Vestigial sideband modulation (VSB) is a type of amplitude modulation (AM) that is particularly useful for transmitting television signals. Here's a breakdown of why the correct answer is correct and why the other choices are incorrect:

### Correct Answer:  
**A: Amplitude modulation in which one complete sideband and a portion of the other are transmitted**

- **Explanation**: In VSB, one full sideband is transmitted along with a portion of the other sideband. This technique is used to reduce the bandwidth required for transmission while still allowing for the recovery of the original signal. It is a compromise between double sideband (DSB) and single sideband (SSB) modulation, providing a balance between bandwidth efficiency and signal quality.

### Incorrect Answers:

- **B: A type of modulation in which one sideband is inverted**  
  - **Explanation**: This describes a form of modulation that does not exist in standard practice. Inverting a sideband is not a characteristic of VSB or any common modulation technique.

- **C: Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier**  
  - **Explanation**: This describes a process related to frequency modulation (FM), not amplitude modulation. VSB is specifically a form of AM, not FM.

- **D: Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation**  
  - **Explanation**: This describes a complex process involving both FM and spread spectrum techniques, which is unrelated to VSB. VSB is a simpler form of AM, not involving spread spectrum or FM.

### Key Points:

- **VSB** is used in television broadcasting because it allows for efficient use of bandwidth while maintaining signal quality.
- **Bandwidth Efficiency**: VSB reduces the bandwidth compared to DSB by transmitting only a portion of one sideband, which is sufficient for signal recovery.

Understanding VSB is important for recognizing how different modulation techniques balance bandwidth and signal quality, especially in applications like television broadcasting.