User guide

SYNCHRONIZATION
57
If the LOCK and TACH lights do not behave as described,
your Express interface is not successfully locking to the
SMPTE time code. This could be a problem with the audio
connections between the tape deck and your Express
interface. It could also be that the SMPTE level is not high
enough. See Appendix C, “Troubleshooting and Customer
Support” page (87).
If the LOCK and TACH lights look OK, but the green
computer OUT LED is not glowing, this means that your
Express interface settings have been altered somehow such
that it is not sending MIDI time code to the computer. To
correct the settings, see Figure 7-1.
Time code display
ClockWorks displays a running update of time code when
the Express interface is converting time code.
Routing MIDI Time Code to other devices
At times, you may need to route MIDI Time Code to a
device connected to one of your Express interface’s MIDI
OUTs. To make time code routings such as these, see “The
MTC In and MTC Out connections” on page 32.
Freewheeling to avoid time code dropouts
When your Express interface encounters a drop-out —a
series of missing or unreadable frames—in the time code,
it “freewheels” past them, pretending that they were not
missing by briefly generating its own code to make up for
the missing frames. The default freewheel value is 4
frames. This means that your Express interface will
continue to generate time code for four more frames after
it stops receiving time code. If it does not receive any more
time code after four frames, it will stop converting.
The factory default base setups have the freewheeling
feature set to 4 frames for fastest response when you stop
the tape deck. The Freewheel amount can be adjusted up
to 32 frames. This allows your Express interface to
maintain lockup even over lengthy SMPTE drop outs.
If you encounter a time code drop out that causes your
Express interface to stop converting for a moment, try
increasing the freewheel amount in ClockWorks. Try
adding just a few frames at a time when adjusting the
amount.
!USB Interfaces Manual Book Page 57 Tuesday, August 16, 2011 11:21 AM