DigiDesign SYNC HD, Manual

Page: 56 / 103

SYNC HD Guide 50
Requirements for Read/Regeneration of LTC,
VITC and MTC
LTC The external positional reference must be
moving at normal, 1x forward speed (±8%).
VITC The positional reference must be LTC or Bi-
Phase/Tach, at any readable speed, forward or
reverse, or when the positional reference is set to
Generate. The SYNC HD will not regenerate
VITC if the positional reference is VITC.
MTC In order for the SYNC HD to regenerate
continuous MTC, the external positional refer-
ence must be moving at normal, 1x forward
speed (±8%). Outside of this speed range and di-
rection, MTC is generated in bursts every 200
milliseconds. This allows MTC-slaved devices to
read VITC or Bi-Phase properly in either direc-
tion, and at speeds down to zero. The SYNC HD
begins regenerating MTC as soon as it again de-
tects a valid positional reference signal.
If the positional reference is LTC or VITC, the
SYNC HD will regenerate time code addresses
that match the incoming time code addresses. If
the positional reference is a Bi-Phase/Tach sig-
nal, the SYNC HD will generate time code ad-
dresses starting at the Bi-Phase preset start time.
(See “Bi-Phase/Tach Starting Frame” on page 47
for more information.)
Generator Preset Mode
In this mode, the SYNC HD generates time code
internally from a start time based upon the Gen-
erator Preset Time. Using either the SYNC Setup
software utility (Windows only) or the
SYNC HD front panel controls, you can start,
stop, resume, and reset time code generation.
When generating time code in Generator Preset
Mode, the SYNC HD time code generator is re-
solved (locked) to one of three possible sources,
based upon the following Generator Reference
rule.
Generator Reference Rule
‹
If the Clock Reference is set to Internal, LTC,
Pilot Tone, Bi-Phase/Tach, Digital (AES/EBU), or
Digital (Word Clock), then the time code gener-
ator will lock to the selected clock reference.
– or –
‹
If the Clock Reference is set to one of the two
video inputs (Video Ref In or Video In), then the
time code generator will reference the
Video Ref In connector.
To optionally mute idle time MTC output,
see “MTC Output and Idle Muting” on
page 56.