*Question E8D05:
What is the most common method of reducing key clicks?*  

*Correct Answer is  A: Increase keying waveform rise and fall times*  

### AI Response: (may contain errors)  

To reduce key clicks, the most common method is to increase the keying waveform rise and fall times. Here's why:

1. **Correct Answer: Increase keying waveform rise and fall times (Choice A)**
   - **Explanation**: Key clicks are unwanted sidebands that occur when a signal is turned on or off too abruptly. By increasing the rise and fall times of the keying waveform, the transitions become smoother, reducing the bandwidth of the signal and minimizing the generation of key clicks. This is similar to using a "soft start" to avoid sudden changes that can cause interference.

2. **Why the Other Choices are Incorrect**:
   - **Choice B: Insert low-pass filters at the transmitter output**
     - Low-pass filters can reduce high-frequency noise, but they do not specifically address the abrupt transitions in the keying waveform that cause key clicks.
   - **Choice C: Reduce keying waveform rise and fall times**
     - Reducing the rise and fall times would make the transitions even more abrupt, increasing the likelihood of key clicks rather than reducing them.
   - **Choice D: Insert high-pass filters at the transmitter output**
     - High-pass filters are used to remove low-frequency components, which is not effective for reducing key clicks caused by rapid transitions in the keying waveform.

3. **Useful Rule of Thumb**:
   - A smoother transition in the keying waveform (longer rise and fall times) results in a narrower bandwidth and fewer key clicks. This can be visualized as a more gradual slope in the waveform, which reduces the sharpness of the signal's edges.

By focusing on the waveform's rise and fall times, you can effectively manage key clicks and improve signal quality.