Clock Modes - Synchronization - RME Audio Hammerfall HDSP AES-32 User Manual

Application examples
DDS allows for a simultaneous change of speed and tune during record and playback. From
alignment to other sources up to creative effects – everything is possible..
DDS allows to intentionally de-tune the complete DAW. This way, the DAW can match instru-
ments which have a wrong or unchangeable tuning.
DDS allows to define a specific sample rate. This feature can be is useful in case the system
randomly changes the sample rate – for unknown reasons. It also prevents a change from Dou-
ble Speed (96 kHz) to Single Speed (48 kHz), which would cause configuration and routing
problems by the changed amount of channels in Double or Quad Wire mode.
11.3 Clock Modes - Synchronisation
AutoSync
The HDSP AES-32 has been equipped with AutoSync, an automatic clock source selection,
which adopts the first available input with a valid digital signal as the clock reference input. The
input currently used as sync reference is shown in the 'System Clock' status field, together with
its current sample frequency.
AutoSync guarantees that normal record and record-while-play will always work correctly. In
certain cases however, AutoSync may cause feedback in the digital carrier, so synchronization
breaks down. To remedy this, switch the HDSP's clock mode over to 'Master'.
Via Pref. Sync Ref (preferred synchronization reference) a preferred input can be defined. As
long as the card sees a valid signal there, this input will be designated as the sync source, oth-
erwise the other inputs will be scanned in turn. If none of the inputs are receiving a valid signal,
the card automatically switches clock mode to 'Master'.
Thanks to its AutoSync technique
and lightning fast PLL, the HDSP is
not only capable of handling standard
frequencies, but also any sample rate
between 28 and 200 kHz. Even the
word clock input, which most users
will use in varispeed operation, allows
any frequency between 28 kHz and
200 kHz.
The HDSP AES-32 outstanding clock
control allows for a synchronization of
the output signal to the word clock's
input signal not only at identical
sample rates, but also at half,
quarter, double and quad sample
rates. A playback of 192 kHz can
easily be synchronized via a 48 kHz
word clock signal.
User's Guide HDSP AES-32 © RME
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