29 May
2009
29 May
'09
4:20 a.m.
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
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On Thu, May 28, 2009 at 8:30 AM, Cameron Stone <camerons.lists@cse.unsw.edu.au mailto:camerons.lists@cse.unsw.edu.au> 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@alsa-project.org <mailto:Alsa-devel@alsa-project.org> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel