Re: LF: Re: WOLF/WSPR Sound card issues

["James Moritz" <james.moritz@btopenworld.com>]

Dear Graham, LF Group,

If an error in sample rate was causing the error in the transmission timing, 
it would also lead to an error of the same percentage in the audio 
frequencies being generated during transmission. I.e. if transmission was 
about 2% short, the transmitted frequency would be about 30Hz higher than 
the nominal value, with an audio frequency around 1500Hz. Likewise the 
reported frequencies on receive would be about 30Hz lower than expected. Do 
you recall if this was the case?
Cheers, Jim Moritz
73 de M0BMU

----- Original Message ----- 
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, September 12, 2009 3:08 PM
Subject: Re: LF: Re: WOLF/WSPR Sound card issues


> 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 ...