Avid Technology Digidesign USD User Manual page 46

• Make sure to have or stripe matching
code on both your LTC and VITC tracks
(and your on-screen video window burn,
if any).
• Make sure to select Auto or the correct
line pair for VITC Read.
For additional information and examples of
Auto Switch LTC/VITC, see "Auto-Switch
LTC/VITC" on page 68 in Appendix A.
Serial Time Code
For MachineControl-equipped Pro Tools
systems, serial time code can be selected for
positional reference. This option is config-
ured from the Pro Tools
Peripherals > Synchronization window. Re-
fer to the MachineControl User's Guide for
configuration instructions and require-
ments.
Bi-Phase/Tach Positional Reference
Strictly speaking, Bi-Phase/Tach signals are
clock reference signals, and do not contain
positional information of their own. How-
ever, they do contain enough information
for the USD to calculate positional infor-
mation.
To calculate positional reference from Bi-
Phase/Tach requires that the USD be given
a starting frame address, and a specific
pulses-per-frame value. Each of these re-
lated settings are explained in the follow-
ing sections.
42 Universal Slave Driver
To use Bi-Phase/Tach for positional
reference, from Pro Tools:
Select Bi-Phase from the Positional Refer-
ence menu, located in the Session Setup
window.
To use Bi-Phase/Tach for positional
reference, from the front panel:
Using the front panel Positional Refer-
ence switch, select Bi-Phase/Tach.
To use Bi-Phase/Tach for positional refer-
ence, from USD Setup:
Select Bi-Phase/Tach under USD Setup's
1
Positional Ref pop-up menu.
Set the starting frame as described in "Bi-
2
Phase/Tach Starting Frame" on page 42.
Set other Input Signals options, as appro-
3
priate.
Selecting Bi-Phase/Tach input signals
Bi-Phase/Tach Starting Frame
In order to use the Bi-Phase/Tach signal as a
positional reference, the USD also needs to
know the time code address for a particular
frame of film. This positional relationship
is established by parking the film device at
a particular frame and setting the USD to
the equivalent time code value using the
Bi-Phase/Tach Starting Frame parameter.
Bi-Phase start frame can not be set from
within Pro Tools.