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
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 MADI channels.
19.3 Clock Modes - Synchronisation
AutoSync
The HDSP MADI 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 AutoSync Ref status field, together with its current sample frequency.
AutoSync guarantees that normal record and
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 PLLs, the HDSP is not only capable of han- dling standard frequencies, but also any sample rate between 28 and 105 kHz. Even the word clock input, which most users will use in varispeed operation, allows any frequency between 28 kHz and 105 kHz.
The HDSP MADI's 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 96 kHz can easily be synchronized via a 48 kHz word clock signal.
SyncCheck
If several digital devices are to be used simultaneously in a system, they not only have to oper- ate with the same sample frequency but also be synchronous with each other. This is why digi- tal systems always need a single device defined as ‘master’, which sends the same clock signal to all the other (‘slave’) devices.
Remember that a digital system can only have one master! If the HDSP MADI’s clock mode is set to Master, all other devices must be set to Slave.
RME’s exclusive SyncCheck technology (first implemented in the Hammerfall) enables an easy to use check and display of the current clock status. The SyncCheck field indicates whether no signal (No Lock), a valid signal (Lock) or a valid and synchronous signal (Sync) is present at each of the digital clock source inputs. The ‘AutoSync Ref’ display shows the current sync source and the measured frequency.
In practice, SyncCheck provides the user with an easy way of checking whether all digital de- vices connected to the system are properly configured. With SyncCheck, finally anyone can master this common source of error, previously one of the most complex issues in the digital studio world.
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