Avid Technology Digidesign USD, User Manual, Page: 36 / 96

Universal Slave Driver 32
Clock References
When used with an external clock refer-
ence, the USD functions as a resolver—so
that Pro Tools and other devices can be
synchronized, or resolved, to a common
clock source.
Selecting a Clock Source
To choose a clock reference from Pro Tools:
■
Choose Display > Session Setup Window,
then select a setting from the Clock Refer-
ence pop-up menu.
To choose a clock reference using the front
panel controls:
■
Push and release the Clock Reference
switch to cycle the USD through its avail-
able clock references.
To choose a clock reference using USD
Setup:
■
Select a setting from the Clock Reference
pop-up menu.
Clock Reference Options
The following sections provide specialized
instructions for each clock reference
choice.
Video Clock Options
Depending upon how the USD is config-
ured, this clock reference may be the Video
Ref In or the Video In connector (for more
details, see “Limitation When Using Front
Panel Clock Reference Switch” on page 32).
For House Sync/Black Burst
Use the USD
Video Ref Input.
For Incoming Video Use the Video In con-
nector.
Serial Time Code with MachineControl
MachineControl-equipped Pro Tools sys-
tems can utilize serial time code. When us-
ing MachineControl with serial time code
as the positional reference, the USD must
be locked to Video Ref. In this scenario, the
USD is set to Generate mode to indicate
that positional information is acquired by
Pro Tools directly over the 9-pin cable, not
through the USD. Consult the MachineCon-
trol User’s Guide for complete serial time
code information.
Limitation When Using Front Panel Clock
Reference Switch
When you choose Video using the front-
panel Clock Reference switch, the USD uses
the signal at the Video Ref In connector. To
choose the signal at the Video In connector
as your clock reference, you must use
USD Setup or Pro Tools.
Configuring the USD Clock Reference from Pro Tools