17 Nov
2009
17 Nov
'09
6:04 p.m.
Am Samstag, 14. November 2009 schrieb Karl Hammar:
Hi Karl, hi LAU users
I've followed the discussion about timing and synchronisation - what do you
think about separation of number crunching and communication (ATNGW100) from
the "dirty business" of ADC.
We need the codec, some kind of amplification, a clean power supply etc. to get
a good S/N ratio - and we need it for a lot of channels.
There exist many (more or less) pro-audio devices with well documented
interfaces (SPDIF/AES-3; ADAT; MADI) - a cheap one is e.g. the Behringer
ADA8000 for about 200 € [1] with eight mic (phantom power) or line inputs and
eight line outputs. The codecs are 24bit(a)44.1/48 kHz [2]
[1] http://www.thomann.de/gb/behringer_ultragain_pro8_digital_ada8000.htm
[2] http://images4.thomann.de/pics/prod/164573_manual_eng.pdf
Regards
Martin Homuth-Rosemann
Folderol:
> On Sat, 14 Nov 2009 09:34:15 -0500
>
...
On the
hardware side, that Atmel development kit (2) looks very
interesting as a proving ground as it already has both the network and
the 48kHz DAC parts built in.
For rough testing it could be used to lock a pair of ADCs. TLC4545ID
looks like a good (cheap) possibility here.
Found it, datasheet at [1], it seems to cost ~12USD. There is no
"start" pin to be able to simultaneously start multiple converters.
And you cannot daisychain this chip. [2] can be daisy-chained, but
with a maximum of eigth channels, but it can be synced.
If we are going to have multiple analog inputs at higt sample rate,
isn't it better to have a parallell interface. With spi the number of
channels will be limited to something like 8 for a 24bit converter.
Plus that the AT32AP7000/AT91SAM9260 only has two spi-busses.
Maybe ad7762 [2] could be useful (28 USD),
(1)
http://www-net.cs.umass.edu/kurose/transport/UDP.html
(2) http://www.atmel.com/dyn/products/tools_card.asp?tool_id=4102
[1] http://focus.ti.com/lit/ds/symlink/tlc4545.pdf
[2] http://www.analog.com/static/imported-files/data_sheets/AD7764.pdf
[3] http://www.analog.com/static/imported-files/data_sheets/AD7762.pdf
Regards,
/Karl