Question
What technique minimizes the bandwidth of a PSK31 signal?
Answer Options
- A) Zero-sum character encoding
- B) Reed-Solomon character encoding
- C) Use of sinusoidal data pulses
- D) Use of linear data pulses
Correct Answer: C
Explanation
The \text{PSK}31 mode is celebrated for its extremely narrow bandwidth (only 31.25 \text{ Hz}), which allows many simultaneous contacts to occur in a small segment of the \text{HF} spectrum. Achieving this narrow bandwidth requires minimizing the spectral energy generated during the transition between symbols (the phase shift).
\text{PSK}31 minimizes bandwidth through the use of sinusoidal data pulses. Instead of abruptly changing the phase of the carrier (which would generate splatter), the transmitter uses a precisely shaped half-cycle sine wave to define the phase transition between symbols. This intentional ‘soft keying’ minimizes the high-frequency components generated during switching, keeping the signal exceptionally clean and narrow.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!