[Fwd: [Lowfer] BPSK and PSK31]
Fri, 23 Apr 1999 08:26:07 -0400
John Matz wrote:
> Hi all
> I would like to make some theoretical analysis comments on BPSK and PSK31.
> CW at 12 WPM is 1 character/second (roughly 10 baud).
> BPSK as used by Lowfers is also about 1 character/second (about 10 baud
> PSK31 is at about 3 characters/second Varicode (about 31 baud).
> This means PSK31 needs about 3 times the RX bandwidth, and roughly 5 dB
> worse sensitivity than BPSK and 2 dB worse than 12 wpm OOK CW. That's due
> to the faster data rate in PSK31. Also there is no way to run at a slower
> speed or data rate and stay in PSK31, right? In BPSK the data rate is
> often slowed down to get better sensitivity, until the equipment or path
> can't stand it. The higher speed of PSK31 improves performance at higher
> frequencies where the TX and RX phase noise and stability (and the tuning
> and the path) aren't as good. As people have observed, a bit faster data
> rate than 10 baud seems to be better at higher freqs.
> Just some thoughts.
> John Matz KB9II
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