[alsa-devel] Increasing maximum sampling frequency?
camerons.lists at cse.unsw.edu.au
Fri May 29 04:20:20 CEST 2009
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.
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 at cse.unsw.edu.au <mailto:camerons.lists at cse.unsw.edu.au>>
> 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.
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