Avid Technology Pro Tools SYNC HD, Manual

Page: 36 / 166

Pro Tools | SYNC HD Guide 30
Bi-Phase/Tach and Clock
Reference
SYNC HD can resolve to Bi-Phase/Tach informa-
tion for use as a clock reference. Bi-Phase/Tach
can synchronize positional reference, but you must
provide a reference
start address (see “Bi-Phase
Position Trimming” on page 36 for other require-
ments). Pro Tools will not lock until the Bi-Phase
signal is present.
To configure Bi-Phase/Tach for SYNC HD clock
reference from Pro Tools:
1
In the
SYNC Setup
section of the Pro Tools Ses-
sion Setup window, select
Bi-Phase
from the
Positional Reference
pop-up menu.
2
Choose
Setup > Peripherals
and click
Synchronization
.
3
Enter the Pulses Per Frame and choose the Input
Signal setting, as described in “Bi-Phase/Tach
Starting Frame” on page 35 and “Bi-Phase/Tach
Signal” on page 35.
To configure Bi-Phase/Tach for SYNC HD clock
reference using the front panel controls:
1
Press the Clock Reference switch to select Bi-
Phase/Tach.
2
Select the appropriate Pulse Per Frame and In-
put Signals parameters, as described in
“Bi-Phase/Tach Starting Frame” on page 35 and
“Bi-Phase/Tach Signal” on page 35.
Typically, when you use Bi-Phase/Tach as the
clock reference you will also be using it as the po-
sitional reference (see “Bi-Phase/Tach” on
page 34.).
To resolve SYNC HD to its internal clock from
Pro Tools:

In the
SYNC Setup
section of the Pro Tools Ses-
sion Setup window, select
Internal/VSO
from
the
Clock Reference
pop-up menu.
To resolve SYNC HD to its internal clock using the
front panel controls:

Press the Clock Reference switch to select In-
ternal/VSO.
Variable Speed Override (VSO)
To fine-tune the speed (and pitch) of Pro Tools or
any device receiving its clock reference from
SYNC HD, you can varispeed the rate of the
SYNC HD crystal-referenced internal clock.
VSO is available at any Positional Reference set-
ting. VSO is not available from the SYNC HD
front panel controls, but can be controlled directly
from Pro Tools.
If the Bi-Phase/Tach reference clock source
is not valid for any reason (such as a poor
connection or other signal transmission
problem), the Locked LED on the far-right of
the SYNC HD front panel flashes. SYNC HD
accepts up to 12V at the Bi-Phase input.
For additional Bi-Phase/Tach signal infor-
mation, see “Bi-Phase/Tach” on page 60.
Effective VSO rates
Sample Rate
(kHz) Rate
Type
Min. (Hz)
Max
(Hz)
44.1 1x 40000 50500
48
88.2 2x 80000 101000
96
176.4 4x 160000 202000
192