Very interesting on the three types of spectra:
So far I 'played' with 3 types of modulation : real BPSK, PSK (amplitudes
enveloped) and what I call 'soft' PSK (gradual phase transitions instead
brute phase jumps).
The spectra (and and block diagram of the modulator) can be found at :
It confirms that :
- BPSK is far too wide to be used with high power on 136kHz (unless you
live in the middle of nowhere or you just don't care about others)
- that PSK has the best (most narrow) bandwidth
- that 'soft' PSK may have some potential as a class-D suitable mode with
an acceptable bandwidth.
I think it would be useful to include a 4th spectra for CW "on-off keying"
as there is nearly a century of experience with sharing frequencies where
there are finite key clicks. One criteria is for BPSK bandwidth to be no
more than a same PEP and same data rate CW emission.