Message-ID: <01C4E107.8A5EB620.actalbot@southsurf.com>
From: Andy <actalbot@southsurf.com>
To: "'rsgb_lf_group@blacksheep.org'" <rsgb_lf_group@blacksheep.org>
Date: Mon, 13 Dec 2004 11:33:15 -0000
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Organization: UKNWN(UK)
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Subject: LF: RE: RE: Re: Frequency errors on PSK31
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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:j.r.moritz@herts.ac.uk] 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
>
>
>
>
>
>  << File: ATT00000.htm >>