*Question E7E09:
What occurs when the input signal levels to a mixer are too high?*  

*Correct Answer is  A: Spurious mixer products are generated*  

### AI Response: (may contain errors)  

When the input signal levels to a mixer are too high, the correct answer is:

**A: Spurious mixer products are generated.**

### Explanation of the Correct Answer:
- **Spurious mixer products** are unwanted signals that can occur when the input levels exceed the linear operating range of the mixer. This happens because the mixer is a non-linear device, and when driven too hard, it can produce additional frequencies that are not part of the original input signals. These spurious products can interfere with the desired output and degrade the overall performance of the system.

### Why the Other Choices are Incorrect:
- **B: Mixer blanking occurs**  
  - Mixer blanking refers to a condition where the mixer output is temporarily suppressed or turned off, usually to avoid interference during certain periods. This is not a direct result of high input levels.

- **C: Automatic limiting occurs**  
  - Automatic limiting is a process used in some systems to prevent distortion by reducing the gain when the input signal exceeds a certain threshold. However, this is not a typical behavior of a mixer itself; rather, it is a function of the preceding or following stages in a system.

- **D: Excessive AGC voltage levels are generated**  
  - Automatic Gain Control (AGC) is used to maintain a consistent output level despite varying input levels. While high input levels can affect AGC circuits, excessive AGC voltage is not a direct consequence of high input levels at the mixer itself.

### Useful Rules of Thumb:
- Always ensure that the input levels to a mixer are within the specified range to avoid distortion and spurious products.
- Monitor the output spectrum for unwanted signals when operating near the mixer’s limits.

This understanding will help you answer questions related to mixer operation and signal processing effectively on the exam.