Re: [linux-audio-dev] Re: GPL Audio Hardware

On 4/5/06, Lee Revell <rlrevell@joe-job.com> wrote:
> On Wed, 2006-04-05 at 19:52 -0500, Richard Smith wrote:
> >
> > 60 channels @192/24 is 35Megs/s. A SCSI cards and Gigabit ethernet
> > interface do much more than that. Perhaps you could not get super low
> > latency running all 60 channels. All 60 channels would take a minimum
> > of 300mS to move across the bus. You would need PCI 64/66 at that
> ^^^^^
> Do you mean microseconds? To move how many frames?

Ah.. yeah.. I _totally_ fsked up the math. Gotta lay off all that
crack. A whole frame of 60 channels @ 24bit is only 1.4 uS. Jeez.
talk about being bad wrong. That's good news though. That means an
fairly low powered FPGA could do that plus a whole lot more.

> Also I don't think 192/24 is really a typical config, most people would
> use 96.

All the more reason to be able to run at 192/24. Using the onboard
PLLs of the FPGA you could pretty much run at whatever sample rate you
wanted with just a firmware change. But clocking at 192k gets 96 and
48 with simple divisors. 44.1 could be a special case. Most of the
fpga now days have more than 1 pll so you could do 1 for the 192
multiples and one for the 44.1 rate.

--
Richard A. Smith