Archimago wrote: 
> Where are you saying is the WM8805 SPDIF receiver in this post? That was
> the SPDIF receiver in the old AUNE X1, not the ASUS Essence One... I
> assume therefore you are the one mistaken.
> 
> "Toslink can exhibit several 100ns of jitter" - do you mean "ps"? I'm
> pretty sure I show 100+ps difference with the Transporter's TosLink vs.
> coaxial if one were to calculate the peaks.
> 
> BTW: What's with the "To me this (your)  exercise is useless and
> misleading" comment? Such an offensive tone is barely constructive in
> this or really any domain don't you think? Suppose you were correct in
> your comments above...  Don't you think it's still useful to document
> the (slight) differences between transport devices and encourage others
> to explore the question since results could vary depending on the SPDIF
> receivers?

Just take a Cirrus CS8416 or a TI DIR 9006 instead of WM8805. They all
have similar specs -- on the intrinsic jitter part. The CS8416 is the
worst here. The Wolfsons WM8805/4 seem to attenuate jitter best.
I'd guess that you'll find one of those three in 95% of all the devices
out there.


No. I mean Nano Seconds. Have  a look at the datasheets or e.g. Phillips
TORX Toslink transmitters. Just  ONE side exhibits theoretically up  to
15ns ( n as in nano)  jitter. Now take the airgaps, the 2nd side, the
cable asf asf. 

It's the WM8805 ( or something else ), which gets that SPDIF jitter
down.  We should not mixup SPDIF jitter specs and I2S jitter specs. On
I2S we need pico second jitter. On SPDIF you can have 100ns and the
receiver will still lock to it.


Besides those transceivers you'll find in quality DACs even more jitter
attenuation methods ( FIFO reclockers, ASRCS asf, the Sabre does it
inside). All these will mess up your measurement results by improving
the digital input signal. 

Measurement equipment or setups are not allowed to change a signal!
Otherwise you'll measure the performance of your source + your
measurement equipment performance.





You might want to read this 'Wolfson'
(http://www.wolfsonmicro.com/documents/uploads/misc/en/Jitter_performance_of_spdif_digital_interface_transceivers.pdf)
document.



People who still think and claim digital is digital just have not
understood how things work.



::: ' Touch Toolbox and more' (http://soundcheck-audio.blogspot.com) :::
by soundcheck
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