Townshend Computer Tools DAT-Link User Manual page 85

9.1 Synchronization
Connecting the External Clock
The external clock is an external device used to synchronize 2 to 6
units. It has 6 identical connectors on its back panel that can be wired to the
DAT-Link
+ units with the provided cables. It is powered by tapping one of the
DAT-Link
+ s power supply. On its front panel, a switch chooses the clock frequency
it generates between 48kHz and 44.1kHz. This switch should be set to the desired
frequency before issuing the commands on the computer.
Once multiple units are connected to the external clock, playback sampling-rate
synchronization can be controlled using the
example, to obtain the sampling rate clock from the external clock, you could use:
naplay -S E48000 file
where the pre x to the sampling rate is an abbreviation for
E
although an external clock is used in the above example, the nominal sampling rate
is still speci ed. This is necessary only when sampling-rate conversion is used to
allow the software to calculate the correct up-sampling or down-sampling ratio. The
value chosen should match the rate selected on the external clock.
Synchronization of start-time for playback or recording can also be achieved using
the external clock. The
DAT-Link
indication that the
signal is high the unit is ready to begin. Furthermore, if an external device forces
the signal low, then the
READY
even if it is ready to do so. Thus, if multiple
via an external clock unit, none of them will begin playback or recording until all
connected units are ready. When the last unit releases
Link
+'s will then begin. The front panel Pause LED indicates the state of the
pin.
READY
Note that to playback or record from a single
connected together it is necessary to override the start-time synchronization. This
can be done by executing the command:
dlmkrdy -u unit_number
These options can be combined to, for example, playback two data les simultane-
ously at the same sampling rate:
naset -u :0 -S E
naset -u :1 -S E
naplay -u :0 file0 -S E48000 &
naplay -u :1 file1 -S E48000
option to
-S
pin of the Sync connector provides an external
READY
+ is ready to begin recording or playback. When this
DAT-Link
+ will not begin recording or playback
DAT-Link
DAT-Link
81
DAT-Link
or . For
naset naplay
. Note that
External
+'s are connected together
DAT-
, all of the
READY
+ while multiple units are
+