Chapter 6: Using Pro Tools | Sync X 29
Bi-Phase/Tach
Bi-Phase/Tach (tachometer) signals are Clock Reference signals that do not contain Positional Reference information of their own.
However, they do contain enough information for Sync X to simulate Positional information. In order to use the Bi-Phase/Tach sig-
nal for Positional Reference, Sync X needs to know the timecode address for a particular frame of film. This positional relationship
is established by parking the film device at a particular frame and setting Sync X to the equivalent timecode value using the
Bi-Phase/Tach Starting Frame parameter. There are several different standards for the number of pulses-per-frame output by
Bi-Phase or Tach devices. You can set Sync X to operate from a choice of several fixed values between 2 and 250 pulses per frame.
The setting should match the PPF rate of the external device’s Bi-Phase/Tach encoder.
To use a Bi-Phase/Tach signal for Positional Reference:
1 Connect the Bi-Phase/Tach reference source to the GPIO, BI-PHASE/TACH IN, PILOT IN DB-25 port on Sync X.
2 In the Pro Tools Session Setup window, select Bi-Phase as the Format for Positional Reference.
3 In the Synchronization page of the Peripherals dialog, select the appropriate Bi-Phase/Tach Wiring setting for the incoming
Bi-Phase/Tach signal:
•
Bi-Phase: FWD = A leads B
•
Bi-Phase: FWD = B leads A
•
Tach: FWD = B is Low
•
Tach: FWD = B is High
4 Select the value for the Bi-Phase/Tach Pulses/Frame setting (from 2 to 250) that matches the PPF rate of the external device’s
Bi-Phase/Tach encoder.
5 Click OK.
Generating and Regenerating Timecode
Pro Tools | Sync X generates LTC and MTC simultaneously, and can obtain time addresses from a variety of sources.
When the Format for Positional Reference is set to Generate, Sync X can generate LTC and MTC from an internal time ad-
dress clock.
When the Format for Positional Reference is set to LTC or Bi-Phase, Sync X generates LTC and MTC based on the time ad-
dress of one of those sources.
When generating LTC, Sync X also generates and outputs MTC regardless of Pro Tools generated MTC (which is configured
and engaged separately).
To generate LTC and MTC from Sync X:
In Synchronization view in the Edit or Transport window, click the GEN LTC button to enable LTC generation. The Format for
Positional Reference is set to Generate automatically. Sync X generates and outputs both LTC and MTC.
Requirements for Read/Regeneration of LTC and MTC
LTC
The external positional reference must be moving at normal, 1x forward speed (+/– 8%).
MTC
In order for Sync X to regenerate continuous MTC, the external positional reference must be moving at normal, 1x forward
speed (+/– 8%). Outside of this speed range and direction, and provided that the
Idle MTC Enabled option is selected in the Syn-
chronization page of the Peripherals dialog, short bursts of MTC will be output approximately every 200 milliseconds. This lets ex-
ternal devices that are clocking to MTC read Bi-Phase properly in either direction, and at speeds down to zero. Sync X begins re-
generating MTC as soon as it again detects a valid Positional Reference signal.
If the Positional Reference is LTC, Sync X will regenerate timecode addresses that match the incoming timecode addresses. If the
Positional Reference is a Bi-Phase/Tach signal, Sync X will generate timecode addresses starting at the Bi-Phase preset start time.
For information about optional mute idle time MTC output, see MTC Output and Idle MTC Enabled Option.
For more information, see Bi-Phase/Tach.
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