From mboxrd@z Thu Jan 1 00:00:00 1970 From: Braddock Gaskill KD5ZVK Subject: Re: user soundmodem problems on Inspiron 8200 i810 chipset... Date: Wed, 10 Mar 2004 13:36:45 -0600 Sender: linux-hams-owner@vger.kernel.org Message-ID: <20040310193645.GA3882@braddock.com> References: <20040309022333.GA4377@braddock.com> <1078861838.2336.1.camel@law3lz8h11.lib.loc.gov> <20040309213542.GA27566@braddock.com> <404F540B.3050309@scs.ch> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <404F540B.3050309@scs.ch> List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Linux-Hams@vger.kernel.org Cc: Thomas Sailer On Wed, Mar 10, 2004 at 06:44:43PM +0100, Thomas Sailer wrote: > >http://braddock.com/soundmodem.png > > Looks like alsa tries to do sample rate conversion, but > "somewhat" imperfectly. Sigh. Does anyone know how to convince The only strange thing about that theory (which I tend to agree probably is what's going on) is that if I do a 9600 samp/sec capture with SOX using the OSS interface, and look at the capture in Octave, I don't see the anomaly. In fact, I can then take the 9600 samp/sec SOX capture of APRS input and use it with an unmodified version of soundmodem in "file" mode and get perfect copy. The command I'm using for the sox capture is: sox -V -r 9600 -t ossdsp /dev/dsp -t wav -b -u -r 9600 /tmp/output4.wav (or -t raw to look at it in Octave) Now, a dmesg reveals an ALSA warning message when the snd-ac97-codec module is inserted: ALSA ../../alsa-kernel/pci/ac97/ac97_codec.c:1861: MC'97 1 converters and GPIO not ready (0xff00) I don't know if that warning is related. Sox (in -V verbose mode) outputs: sox: Input file /dev/dsp: using sample rate 9600 size bytes, encoding unsigned, 1 channel sox: Input file /dev/dsp: comment "/dev/dsp" sox: Writing Wave file: Microsoft PCM format, 1 channel, 9600 samp/sec sox: 9600 byte/sec, 1 block align, 8 bits/samp sox: Output file /tmp/output4.wav: using sample rate 9600 size bytes, encoding unsigned, 1 channel sox: Output file: comment "/dev/dsp" sox: Finished writing Wave file, 17408 data bytes 17408 samples At any rate, it's at least good to have these findings in the list archives for others if nothing else. braddock gaskill (KD5ZVK)