*Question E8A11:
Which of the following is a measure of the quality of an analog-to-digital converter?*  

*Correct Answer is  A: Total harmonic distortion*  

### AI Response: (may contain errors)  

To determine the quality of an analog-to-digital converter (ADC), we look at various performance metrics. The correct answer is:

**A: Total harmonic distortion (THD)**

### Explanation of the Correct Answer:
- **Total Harmonic Distortion (THD)** measures the distortion introduced by the ADC when converting an analog signal to a digital signal. It quantifies how much of the output signal is made up of harmonics (multiples of the fundamental frequency) compared to the fundamental frequency itself. A lower THD indicates a higher quality ADC, as it means the output signal closely resembles the input signal.

### Why the Other Choices are Incorrect:
- **B: Peak envelope power (PEP)**  
  - PEP is a measure of the maximum power of a signal, particularly in the context of RF transmissions. It does not assess the quality of an ADC but rather the power output of a transmitter.

- **C: Reciprocal mixing**  
  - Reciprocal mixing refers to a phenomenon in radio receivers where two signals mix in a non-linear way, causing unwanted interference. This concept is related to receiver performance, not ADC quality.

- **D: Power factor**  
  - Power factor is a measure of how effectively electrical power is being converted into useful work output. It is primarily used in AC power systems and does not apply to the performance of ADCs.

### Summary:
- **Total Harmonic Distortion (THD)** is the key metric for evaluating ADC quality, as it directly relates to the fidelity of the signal conversion process. The other options pertain to different aspects of signal processing or power systems, making them irrelevant in this context.