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]> To: <digitalradio@yahoogroups.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, "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 >> > >> > > > > ------------------------------------ > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > 30M digital activity at http://www.projectsandparts.com/30m > > Recommended software : DM780, Multipsk, FLDIGI, Winwarbler ,MMVARI. > Yahoo! Groups Links > > > > >
