96Khz problems

[MWP]

Hi all,

Im having problems getting my DAC (DIR1703, PCM1730) working with 96Khz sampling rates.
It works perfectly with 44100 and 48000, but at anything above 48000, i get a no signal indicator from the DIR1703.

The DIR170 is running in PLL mode, 256fs, using a 12.288Mhz crystal.
According to the DIR1703, this setup in PLL mode should have no problem syncing to a 96Khz signal.

Anyone have any ideas as to why i should have problem with this?

Details on my DAC are here:
http://www.overclockers.com.au/~mwp/dac3

Thanks.

[tiroth]

How do you precondition the S/PDIF signal? It is possible that a marginal input circuit works at 48kHz but not at 96kHz.

[MWP]

Hmmm.

Well its optical out from a soundcard (Envy24HT) -> Toslink Recv -> DIR1703.
Not much inbetween.

[Stones]

mwp

qoute from the dir1703 data sheet:
if CKSEL is connected to UNLOCK which indicates the S/PDIF decoding status and the PLL2 lock state, the system clock can be selected automatically when the S/PDIF signal is active and the bit rate is detected.

from what i see from the diagram on your web site this is not the case. (i may be well of base but i hope it helps)

[DragonMaster]

Is your crystal enough fast?
I already saw some DACs that their max Hz and bytes depended also on the clock.

[Stones]

You are useing scko to the dac try it at 128fs as table 3 in the data sheet

[MWP]

Originally posted by mark stones
mwp

qoute from the dir1703 data sheet:
if CKSEL is connected to UNLOCK which indicates the S/PDIF decoding status and the PLL2 lock state, the system clock can be selected automatically when the S/PDIF signal is active and the bit rate is detected.

Thanks for the sugestion, but after a quick check, CKSEL grounded means it always in PLL2 sync mode.

You are useing scko to the dac try it at 128fs as table 3 in the data sheet

Yeh, i might give that a try.
Im thinking it wont help though, as the setup im using accoring to the table should be fine at 96khz @ 256fs.

I pulled the TOSLINK recv & trans out of $30 COAX->TOSLINK converters... i wonder if they are cheap units that cant handle 96khz.

[Stones]

Originally posted by MWP


Thanks for the sugestion, but after a quick check, CKSEL grounded means it always in PLL2 sync mode.

As you have pointed out it is probably your toshlink (how does the signal look on a scope).

sorry I realised after I had posted that if you are not getting the lock signal then sync mode wont help.

[rlim]

MWP,
How is it possible to get a sampling rate of 44.1KHz with a 12.288MHz crystal ? I am looking at page 8, table 3 of the DIR1703 datasheet where 12.288MHz is not a crystal oscillator frequency that selects the 44.1KHz sampling rate....

[MWP]

Originally posted by rlim
MWP,
How is it possible to get a sampling rate of 44.1KHz with a 12.288MHz crystal ? I am looking at page 8, table 3 of the DIR1703 datasheet where 12.288MHz is not a crystal oscillator frequency that selects the 44.1KHz sampling rate....

Its possible to get any frequency when using pll sync mode.