*Question E4E03:
Which of the following types of noise are removed by a noise blanker?*  

*Correct Answer is  B: Impulse noise*  

### AI Response: (may contain errors)  

The correct answer to the question about noise blankers is **B: Impulse noise**. Here's a breakdown of why this is the case and why the other options are incorrect.

### Why the Correct Answer is Correct:
- **Impulse Noise**: Noise blankers are specifically designed to remove short-duration, high-amplitude noise spikes, which are characteristic of impulse noise. This type of noise can be caused by electrical interference from devices like motors or lightning strikes. The noise blanker works by detecting these sudden spikes and effectively "blanking" them out, allowing for clearer reception of the desired signal.

### Why the Other Choices are Incorrect:
- **A: Broadband White Noise**: 
  - Broadband white noise consists of a wide range of frequencies and is typically continuous. Noise blankers are not effective against this type of noise because they target transient spikes rather than continuous noise.

- **C: Hum and Buzz**: 
  - Hum and buzz are usually caused by alternating current (AC) interference, often at a specific frequency (like 60 Hz in the U.S.). Noise blankers do not address this type of noise, as they are designed for impulsive noise rather than continuous or periodic interference.

- **D: All these choices are correct**: 
  - Since only impulse noise is effectively removed by noise blankers, this option is incorrect.

### Summary:
- Noise blankers are effective against **impulse noise** but not against **broadband white noise** or **hum and buzz**. Understanding the specific types of noise that noise blankers can mitigate is crucial for effective amateur radio operation. 

This knowledge will help you in both the exam and practical applications in the field.