Thanks, Patrick!
If I understand this, then, here is what I should expect:
My sound card calibrates to 48009.37, which is .9998% fast
I transmit with an audio frequency of 2415 Hz
I am therefore actually transmitting on 2439 Hz, or .9998% higher
than indicated
Does that sound right?
Tnx es 73
Dave KB3MOW
Patrick Lindecker wrote:
>
> Hello Dave,
>
> It is simple. If the offset in sampling frequency is x% and the true AF
> frequency is f0, the displayed frequency f will be equal to
> f=f0*(1-x/100)
> Example: if the sampling offset is +1% and f0 is 1000 Hz, the frequency
> displayed will be equal to 1000*(1-0.01)=990 Hz
>
> 73
> Patrick
>
> ----- Original Message -----
> From: "Dave" <[EMAIL PROTECTED] <mailto:dcorio%40zitomedia.net>>
> To: <digitalradio@yahoogroups.com <mailto:digitalradio%40yahoogroups.com>>
> Sent: Tuesday, October 07, 2008 3:57 PM
> Subject: [digitalradio] Re: Sound card question
>
> > Thanks, Simon! It makes sense that if the "native" speed is 48K, any
> > other speed would require some type of "conversion".
> >
> > One more question, if I can impose on your good nature!
> >
> > What impact, if any, does the error in sampling rate have on any
> > TX/RX offset? During the Tara Rumble I noticed that almost every
> > station that responded to my CQ, came back a bit lower in frequency
> > than mine. One station I responded to even told me I was off-
> > frequency. I don't believe my IC-746 has any offset, and my RIT/XIT
> > was off. Does that large error rate of 6984 ppm create an offset, and
> > can I determine how great it is?
> >
> > Tnx es 73
> > Dave KB3MOW
> >
> >
> > --- In digitalradio@yahoogroups.com
> <mailto:digitalradio%40yahoogroups.com>, "Simon Brown \(KNS\)"
> > <[EMAIL PROTECTED]> wrote:
> >>
> >> It means that the drivers are better - the internal clock runs at
> > 48kHz,
> >> other rates are created by either the driver or (very often)
> > Windows.
> >> Windows XP does not do a good job of this, VISTA however is
> > excellent at
> >> converting the sample rates.
> >>
> >> Simon Brown, HB9DRV
> >> www.ham-radio-deluxe.com
> >>
> >> ----- Original Message -----
> >> From: "Dave 'Doc' Corio" <[EMAIL PROTECTED]>
> >> > I've calibrated my sound card (Diamond PCI) two ways, using
> > MMSSTV
> >> > at 48000 Hz, and MMTTY at 11025 Hz. Here are the results of the
> >> > calibration:
> >> >
> >> > MMSSTV 195 PPM 48009.37
> >> >
> >> > MMTTY 6984 PPM 11102
> >> >
> >>
> >
> >
> >
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> >
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> >
> >
> >
>
>
