The A/D chip is an Analog Devices 7928. It can do 2 mega-samples per second, multiplexed across 8 inputs. The USB audio interface is provided by my firmware code, assisted by the AVR AT90USB647 micro which has some low-level USB support. HTH. Cameron. Alex Austin wrote: > By Codec, I think he's asking about the A/D chip. For example, the TI > PCM2902E is a stereo USB audio codec. > > - Alex Austin > (651) 238-9273 > > "...and then I visited Wikipedia ...and the next 8 hours are a blur." > > > On Thu, May 28, 2009 at 8:30 AM, Cameron Stone > <camerons.lists@xxxxxxxxxxxxxxx <mailto:camerons.lists@xxxxxxxxxxxxxxx>> > wrote: > > Daniel Mack wrote: > > On Thu, May 28, 2009 at 11:47:34AM +1000, Cameron Stone wrote: > >> I've got a USB microphone application that I want to sample at > 256000 8 > >> bit samples per second so I can listen to bats. I know that my device > >> can get close to that rate, but alsa seems to restrict sampling > rates to > >> 192kHz. > > > > Just out of curiosity - which microphone and what kind of codec > are you > > using for such frequencies? > > I don't know which microphone but I can find out if you're interested. I > do know that its sensitivity starts at 10kHz, if that helps. > > There is no codec used. I'm using Type I (uncompressed PCM) because it's > being powered by an AVR running at 16MHz and there's not enough clock > cycles to encode the samples. > > Cameron. > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@xxxxxxxxxxxxxxxx <mailto:Alsa-devel@xxxxxxxxxxxxxxxx> > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel > > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
