*Question G8B11:
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?*  

*Correct Answer is  C: The sum and difference*  

### AI Response: (may contain errors)  

To understand the output frequencies of a mixer, we need to look at how a mixer operates. A mixer takes two input signals: the Local Oscillator (LO) frequency and the Radio Frequency (RF) input frequency. The output of the mixer will include both the sum and the difference of these two frequencies.

### Correct Answer: C - The sum and difference

- When you mix two frequencies, the output will contain:
  - The sum frequency: $f_{out} = f_{LO} + f_{RF}$
  - The difference frequency: $f_{out} = f_{LO} - f_{RF}$

This is a fundamental property of mixers, which is why the correct answer is "the sum and difference."

### Why the other choices are incorrect:

- **A: The ratio**
  - Mixers do not produce output frequencies based on the ratio of the input frequencies. Ratios are not a characteristic of mixing.

- **B: The average**
  - The average of the two frequencies is not produced by a mixer. The output does not represent a central value like an average.

- **D: The arithmetic product**
  - The product of the two frequencies is not generated in the output of a mixer. Mixers specifically create sum and difference frequencies, not products.

### Summary

In summary, when using a mixer, remember that the output will always include the sum and difference of the input frequencies. This is a key concept in understanding how mixers work in radio communications.