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Message-ID: <A09F16DB283543A7951F74093C4B593C@JimPC>
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
References: <00c701c9818b$2aac4520$6401a8c0@asus> <16976E02F609403791409C408C93AFCA@AGB> <3692CCEF55434A78A271B29E8D4BC318@JimPC> <49817638.9070007@telia.com>
In-Reply-To: <49817638.9070007@telia.com>
Date: Thu, 29 Jan 2009 14:17:18 -0000
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Subject: Re: LF: WSPR - G0NBD
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Dear Johan, Graham, LF Group,

If the shorter frame length is due to a sample rate error, there should also 
be a corresponding upward shift in the audio output frequencies. If we take 
M0LMH's figure of 1.5 seconds shorter, the M0BMU PC as being correct, and a 
frame length around 110s this implies a sample rate error of about 1.4%. 
This means that the audio coming out of Graham's PC at around 1500Hz should 
be about 20Hz higher than the nominal value. Is there actually a significant 
frequency error, Graham?

Cheers, Jim Moritz
73 de M0BMU

----- Original Message ----- 
From: "Johan H. Bodin" <jh.bodin@telia.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, January 29, 2009 9:26 AM
Subject: Re: LF: WSPR - G0NBD


> Dear Jim, LF,
>
> that is a clear evidence of a soundcard sampling rate error. I am quite 
> sure
> that all timing in the WSPR software is derived from the sampling 
> frequency and,
> if memory serves me, the WSPR program uses a sampling rate of 12kHz. If 
> the
> soundcard does not support this rate and/or has a "physical" sampling rate 
> that
> is not a multiple of 12kHz (for example 44.1 kHz), then the driver or 
> window$
> will kick in a "resampler" between the soundcard and the WSPR application 
> which
> is asking for 12kHz. Many such resamplers are known to be inaccurate...
>
> 73
> Johan SM6LKM
>