On Sat, 26.09.09 20:37, Gary Huntress (gary.huntress at gmail.com) wrote: > I have been trying for some time to get one sound-based application > running. The application is soundmodem > http://www.baycom.org/~tom/ham/soundmodem/ and is foundational to > linux ax25 and ham radio applications. Its simplest configuration is > to connect the audio from a ham radio to the mic input. Soundmodem > will demodulate the binary data from the audio stream. Uh, generally I'd suggest using the low-evel ALSA-devices directly for low-level applications such as soft modems, i.e. bypassing PA. > Soundmodem has been around for many years and is mature and is known > to work on older linux distributions. I have tried 3 different > laptops with Ubuntu 8 and 9, and Fedora 10 and 11. I have the same > difficulty on all attempts. I can hear the audio, I can mix/change > the audio level, and I can display the audio waveform using the built > in oscilloscope. Occasionally it will detect the carrier but > soundmodem will not decode any audio data. > > I have saved a screenshot here http://www.freesql.org/soundmodem.png > and you can see evidence of some kind of digital pulse train that is > corrupting the audio stream. Could this be a configuration problem > relating to sampling? I do know that soundmodem uses /dev/dsp and I > start the app using padsp, also it reports that its sampling rate is > 9600. I am sorry, but I fear I cannot help you much here. Running a softmoem via padsp sounds very messy to me though. The software really should be updated to use the ALSA API. /dev/dsp is not supported anymore in Fedora 11 and newer, and the interface has been deprecated for 10 years now or so. If your app still uses /dev/dsp someone should coming out of the rock he has been living under. Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net http://0pointer.net/lennart/ GnuPG 0x1A015CC4
