*Question E7B03:
What circuit is required at the output of an RF switching amplifier?*  

*Correct Answer is  A: A filter to remove harmonic content*  

### AI Response: (may contain errors)  

To understand the requirements for the output of an RF switching amplifier, let's analyze the correct answer and the other options.

### Correct Answer: A filter to remove harmonic content

- **Explanation**: RF switching amplifiers are designed to amplify signals at specific frequencies. However, they can also generate unwanted harmonic frequencies due to non-linearities in the amplification process. A filter at the output is necessary to remove these harmonics, ensuring that only the desired frequency components are transmitted. This helps to comply with regulatory standards and reduces interference with other communication systems.

### Why the Other Choices are Incorrect:

- **B: A high-pass filter to compensate for low gain at low frequencies**  
  - **Explanation**: While high-pass filters can be used in some applications, they are not specifically required at the output of an RF switching amplifier. The gain at low frequencies is not typically a concern for RF amplifiers, which are designed to operate efficiently at their intended frequency range.

- **C: A matched load resistor to prevent damage by switching transients**  
  - **Explanation**: While a matched load is important for maximizing power transfer and minimizing reflections, it is not specifically a circuit requirement at the output of an RF switching amplifier. The primary concern is filtering out harmonics rather than just protecting against transients.

- **D: A temperature compensating load resistor to improve linearity**  
  - **Explanation**: Temperature compensation is generally more relevant in linear amplifiers to maintain performance across varying temperatures. In RF switching amplifiers, the focus is on switching efficiency and harmonic suppression rather than linearity, making this option less relevant.

### Summary

In summary, the output of an RF switching amplifier requires a filter to remove harmonic content to ensure clean signal transmission. The other options do not address the primary function of the amplifier or are not necessary for its operation. 

### Useful Rule of Thumb

- **Harmonic Filtering**: Always include a filter at the output of RF amplifiers to ensure compliance with spectral purity requirements and to minimize interference with other signals.