Question
What is the most common method of reducing key clicks?
Answer Options
- A) Increase keying waveform rise and fall times
- B) Insert low-pass filters at the transmitter output
- C) Reduce keying waveform rise and fall times
- D) Insert high-pass filters at the transmitter output
Correct Answer: A
Explanation
Key clicks are caused by the rapid, abrupt turn-on and turn-off of the Continuous Wave (\text{CW}) signal, which generates wideband sidebands. To reduce these unwanted sidebands, the signal envelope must be smoothed out, making the transition less sudden.
The most common method of reducing key clicks is to increase keying waveform rise and fall times (sometimes called ‘shaping the keying waveform’). This process slows down the transition time of the signal envelope, smoothing the resulting \text{RF} pulse and significantly reducing the energy contained in the high-frequency sidebands, thereby minimizing adjacent channel interference.
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