Message-ID: <2EF7A94CAA43488987433D9972EE4279@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <4AAB7F2D.25346.12CA10F@dave.davesergeant.com> <925667FA055F4AEEB8A57B77C90220B3@JimPC>
In-Reply-To: <925667FA055F4AEEB8A57B77C90220B3@JimPC>
Date: Sat, 12 Sep 2009 15:08:37 +0100
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Subject: Re: LF: Re: WOLF/WSPR Sound card issues
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Jim,

Re the  size of error

With the  delta-4 card, the  tx frame could be observed to  be  some  2 or 
more seconds short of the  expected time  window

1 % ~  1.2 seconds , 2 %  ~ 2.4  seconds, assumedly indicating the clock on 
the  card runs fast, but as to the  influence of the system by the 
software, dma, irq etc  Im not  sure, one problem is I expect is the 
soundcards are not  designed to be the  interface for  a accurate  frequency 
meter / generator and as such compromises 'must' exist ...

The only  comparison I can think of is the running of a movie at  shot at 
24 fps  for projection , on a tele cinie system at  25 fps to  sync with the 
uk 50 hz frame rate  , giving a lift in the sound  pitch of + ~ 4 % ? , I 
know that this dose generate  irate phone  calls from musicians pointing out 
that orchestras appear to  be   'sharp' but not many  hi .. so its possible 
a tolerance of  2 %  may be accepted

G .

--------------------------------------------------
From: "James Moritz" <james.moritz@btopenworld.com>
Sent: Saturday, September 12, 2009 1:33 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: LF: Re: WOLF/WSPR Sound card issues

>
> Dear Dave,
>
> AC 97
> (http://download.intel.com/support/motherboards/desktop/sb/ac97_r23.pdf )
> specifies 48kHz as the basic, obligatory sample rate for compliant sound
> cards, so yours should certainly be able to do it - to find more info, you
> could try looking for the audio codec chip on the motherboard - usually a
> very tiny square 48pin thing near the audio connectors, and searching 
> using
> its type number. But I guess what sample rate is actually used will depend
> on software, drivers and so forth - perhaps someone with experience of PC
> sound card programming could advise. Looking at the audio settings in the
> Windows control panel may well tell you what sample rates are possible.
> Also, some software allows you to select different sample rates, for
> instance Spectrum Lab, but not Argo as far as I know.
>
> The errors you are getting in the measured frequency seem to be enormous - 
> 2
> or 3%, which would certainly give rise to problems.
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
> ----- Original Message ----- 
> From: "Dave Sergeant" <dave@davesergeant.com>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Saturday, September 12, 2009 11:59 AM
> Subject: LF: WOLF/WSPR Sound card issues
>
>
> It seems that both WOLF and WSPR are
>> designed for current sound cards which have 48,000 and 96,000 clock
>> rates. Mine is obviously from the old stable so has 44,100 etc rates.
>>
>> For information it is the sound card interface built into the
>> motherboard, an ASR Rock K7S41GX dating from 2003 with generic AC'97
>> sound. Zilch more given about its spec in the manual.
>>
>
>
>



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