Amateur Extra › E8 Signals and Emissions › E8C03
E8C03
Why should the phase of a PSK signal be changed at the zero crossing of the RF signal?
Pick an answer to check it.
Answer: A. To minimize bandwidth
Changing phase when the RF signal crosses zero avoids sudden jumps in the waveform. Sudden jumps create extra sidebands, so this keeps bandwidth small.
Tip: Switch at zero crossing to stay narrow.