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LF: RE: RE: Re: Frequency errors on PSK31

To: "'[email protected]'" <[email protected]>
Subject: LF: RE: RE: Re: Frequency errors on PSK31
From: Andy <[email protected]>
Date: Mon, 13 Dec 2004 11:33:15 -0000
Importance: high
Organization: UKNWN(UK)
Reply-to: [email protected]
Sender: [email protected]
I don't know - and guess it is very dependent on the quality of the demodulation software. For example, what is the loop bandwidth of the bit recovery clock? Some PSK31 demodulators seem to do a better job than others when fed with identical signals.
Andy


On Monday, December 13, 2004 11:14 AM, james moritz [SMTP:[email protected]] wrote:
Dear Andy, Wolf, LF Group,



But what effect does an error in the bit clock have, i.e. if the period of
each bit is not exactly 32ms?



Cheers, Jim Moritz

73 de M0BMU



.As PSK31 uses differential coding, it is the phase change over the 32ms
signalling period due to freqeuncy error that is important.  If for BPSK, we
need to maintain the phase to less than 90 degrees to remove the ambiguity,
so 90/360 / 32ms = 7.8Hz freq error permissible.



For noisy signals, the determination of correct phase becomes worse, so
error rate will progressively worsen with tuning error.



Andy  G4JNT





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