On Wed, 10 Dec 2003 21:04:54 +0000, Ian Molton wrote:

On Wed, 10 Dec 2003 17:56:14 +0000 (UTC)
(Stewart Pinkerton) wrote:

With the 'async' SPDIF you will hear every bit correctly (and thats
still dependant on the conversion method). with a reclocked output,
given the clock will NEVER be a perfect match for the SPDIF clock
anyway, you are garaunteed to either drop or stretch a whole bit at
some point. ick.

No, this is simply not true - although it depends on an adequate
buffer.

No, you ARE wrong.

No, I'm right - you appear not to understand how domestic digital
audio works.

there are two scenarios, and jitter really isnt an issue, becaue

Scenario 1:

Two clocks are a *perfect* frequency match. Unheard of unless they are physically
synchronised, which isnt what we are discussing, so discard this scenario.

Agreed.

Scenario 2:
The two clocks are not a prefect match, the DAC clock is either slower or faster than the
data sources clock.

in this case, if its faster, it will (periodically) drain all its buffering, no matter how much
there is, and will end up stretching bits to fill the gap (or playing silence, whatever)

Not relevant to CD, which has a defined 74 minute maximum, and there
do exist fully buffered true reclocking systems such as the Meridian
800 series, which certainly does *not* drop bits.

if its slower, it will, periodically end up with the buffer over-filling and bits will be lost.

See above.

jitter is simply noise above, and will average out to nothing.

This however will not help the FM distortion which it causes in the
analogue output of the DAC.................

If it DIDNT cancel out, it'd
effectvely be a frequency drift of the data sources clock, which is no longer called jitter (duh).

such a 'drift' would imply a loss of data

There will however be *no* loss of data in a domestic audio situation,
so you are flat-out *wrong*.

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

For God's sake, trim your line lengths!!!
--

Stewart Pinkerton | Music is Art - Audio is Engineering