Steinberg Nuendo DD8 Mode D'emploi page 31

• As long as it does not cause functional problems, jitter is only affecting AD- and
DA-conversion. For completely digital devices like the Nuendo DD 8 jitter is vir-
tually meaningless because the data remains unaltered even with high jitter.
The end of these problems should have been the so called Superclock,
which uses 256 times the word clock frequency. The PLL for multiplying
is no longer needed, and the clock can be used directly. But in practise
Superclock proved to be much more critical than word clock. A square
wave signal of 11 MHz distributed to several devices - this simply
means to fight with high-frequency technology. Reflections, cable
quality, capacitive loads - at 44.1 kHz these factors may be ignored, at
11 MHz they are the end of the clock network. Superclock was, how-
ever, not widely accepted. This non-standard procedure is therefore
not built-into the Nuendo DD 8.
The usage of word clock with ADAT optical is critical too. The Nuendo
DD 8 always uses a Bitclock PLL, no matter if the clock reference is word
clock or ADAT. Thanks to its very fine resolution this exceptional circuit
is able to follow the complete vari-speed range of the ADAT recorder
without losing a sample. Mayn other devices use a much coarser word
clock PLL to track the ADAT input. When changing the sample rate
(speed) fast, some bits are already sampled invalidly before the fre-
quency is corrected. Drop outs and crackling will be the audible result.
So as long as you are working with the Nuendo DD 8 - no problem.
Working with devices of other manufacturers you may experience drop
outs when the sample rate changes only slightly.
The TDIF format is especially critical with respect to word clock. We
have mentioned this in different places of this manual:
When the Nuendo DD 8 is slave no additional word clock connection is
necessary. In case DA88 and/or DA38 are slave the word clock output of
the Nuendo DD 8 has to be connected to the word clock input of the
first (master) recorder. When using more than one recorder a special
sync cable (Tascam part number PW-88S) is needed.
What you do not need to know: the Nuendo DD 8 takes care of the first
DTRS machine's properties, the DA-88, and it can be used together with
this device without further settings.
NUENDO DD 8
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