I have never played with a computer sound card other than the typical plug it in and let the various program drivers interface to it.
I bet the sound card is a simple ADC and software looks at the wave form using a look up table that compares what is received and reacts. DTMF is much more complex, simple in theory, but can be complex. With varying tone levels, distortion, harmonics, etc the wave form changes drastically. Dedicated circuits and ICs do a much better job. 73, ron, n9ee/r >From: Nate Duehr <[EMAIL PROTECTED]> >Date: 2008/03/26 Wed AM 04:22:02 CDT >To: [email protected] >Subject: Re: [Repeater-Builder] DTMF Decoder > > >On Mar 25, 2008, at 4:33 PM, [EMAIL PROTECTED] wrote: >> I still don't understand why the other program I ran on >> the same machine with the same sound card and the same >> connections had no problem decoding. > >That's easy. Better written software. > >-- >Nate Duehr, WY0X >[EMAIL PROTECTED] > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
