Avid Technology Digidesign USD, User Manual, Page: 37 / 96

Chapter 4: Using the USD 33
If you have only a single video source, and
since USD uses different video inputs de-
pending on configuration, you may want
to follow the wiring tip below to ensure
that you have full functionality in all con-
figurations:
To work with a single video source:
1
Connect the video signal to Video Ref In.
2
Run a short BNC jumper cable from the
Video Ref Thru connector to the Video In
connector.
3
Connect the Video Out signal to the
video input of your “destination” VTR or
video editing system.
The issue of which video connector is used
also matters when choosing a positional
reference. For instance, when the USD is in
Generate mode and Video is the current
clock reference, the time code reference for
the generator is always from the Video Ref
In connector.
However, if you select a positional refer-
ence other than Generate, then the signal
at the Video In connector is used.
☞ For more video signal information, refer to
“Video and VITC Signals” on page 67 in Ap-
pendix A.
Digital AES/EBU, Word Clock and
Super Clock
To resolve Pro Tools/USD to external
AES/EBU, Word Clock or Super Clock:
From Pro Tools
■
Select the appropriate digital clock refer-
ence from the Clock Reference pop-up in
the Pro Tools Session Setup window.
Using the front panel controls
1
Press the front panel Clock Reference
switch to select Digital as the clock refer-
ence.
2
Press Set.
3
Press Up or Down until Digital Reference
(dI6 rEF) is displayed in the LED.
4
Press Set again. The LED Time Code Dis-
play displays the current digital reference,
which will be:
• AES/EBU (AES-E8U), or
• Super Clock (256 CLOC), or
• Word Clock (I CLOC)
5
Use the Down and Up switches to select
the desired digital clock.
6
When the desired option is displayed,
press Set.
Using USD Setup
■
Select the appropriate Digital clock refer-
ence option from the Clock Ref pop-up
menu.
If the chosen clock reference source is un-
available, or the current configuration is
not valid, the Locked LED on the far-right
of the USD front panel will flash.
Additional Digital Clock Information
AES/EBU
The USD AES In connector only
recognizes and uses the clock portion of an
incoming AES/EBU audio signal. All audio
information will be ignored and will not be
passed to the USD AES Out connector.