*Question E8A04:
What is “dither” with respect to analog-to-digital converters?*  

*Correct Answer is  B: A small amount of noise added to the input signal to reduce quantization noise*  

### AI Response: (may contain errors)  

Dither is a technique used in analog-to-digital converters (ADCs) to improve the quality of the digital representation of an analog signal. Here's a breakdown of why the correct answer is correct and why the other choices are incorrect:

### Correct Answer:  
**B: A small amount of noise added to the input signal to reduce quantization noise**

1. **Explanation**:  
   - Dither involves adding a small amount of random noise to the input signal before it is converted from analog to digital. This process helps to randomize the quantization error, which is the difference between the actual analog value and the nearest digital value.
   - By spreading the quantization error over a wider range of values, dither makes the error less noticeable and can improve the perceived quality of the digital signal, especially in audio applications.

### Incorrect Answers:

1. **A: An abnormal condition where the converter cannot settle on a value to represent the signal**  
   - This describes a malfunction or instability in the ADC, not the intentional process of dithering. Dither is a controlled addition of noise, not an abnormal condition.

2. **C: An error caused by irregular quantization step size**  
   - Quantization error is inherent in the conversion process due to the finite resolution of the ADC, but it is not caused by irregular step sizes. Dither is used to mitigate the effects of quantization error, not to address irregular step sizes.

3. **D: A method of decimation by randomly skipping samples**  
   - Decimation involves reducing the sample rate of a signal, typically by averaging or filtering, not by randomly skipping samples. Dither is unrelated to decimation; it is about adding noise to improve quantization.

### Useful Concept:

- **Quantization Noise**:  
  Quantization noise is the error introduced when mapping a continuous range of values to a finite set of levels. Dither helps to mask this noise by making it less correlated with the signal, thus improving the overall quality of the digital representation.