Avid Technology Digidesign USD, Руководство пользователя, Страница: 29 / 96

Chapter 3: USD Hardware and Software Overview 25
inserting VITC. The only invalid positional
reference modes are VITC or Auto Switch
LTC/VITC. The USD can’t read VITC and
generate new VITC at the same time.
13. Pitch Memory Enabled
When selected, the USD will remain at a
pitch (sample rate) that corresponds to the
last known incoming time code speed.
When deselected, the USD will revert to the
selected sample rate. This feature enables
the USD to learn the time code form a spe-
cific source during successive lockups, so
lock up times can be optimized.
If Pitch Memory is disabled and the se-
lected external clock reference is not avail-
able, then the USD will revert to the nomi-
nal, selected internal sample rate setting.
14. Idle MTC Enabled
Controls MTC Output during idle (play
stopped). When enabled, MTC is continu-
ously output. When not enabled, MTC out-
put is muted when playback is idle. See
“MTC Output and Idle Muting” on page 51
for details.
15. Window Dub
Settings for the USD character genera-
tor/window dubbing features. (These con-
trols are also available from within the
Pro Tools Peripherals dialog.)
Complete Window Dub instructions are
provided in the section “Generating a Win-
dow Burn” on page 51.
16. Bi-Phase/Tach Parameters
Used for specialized applications that in-
volve film or other equipment that output
Bi-Phase/Tach information. These parame-
ters must be set to match the Bi-Phase or
tach source to achieve lock. See “Positional
Reference and Bi-Phase/Tach” on page 38
for more information.
17. Generator/Bi-Phase Preset
Serves two functions, as determined by the
current USD mode:
Generate mode
Sets the time code start
time directly by clicking in the
Hrs:Min:Sec:Frm fields and typing in a
value. The Tab key will cycle though the
fields.
– or –
Bi-Phase/Tach Mode
Zeros the time code
counter, to allow the USD to generate time
code in relation to the pulses of the incom-
ing Bi-Phase/Tach information. Establishes
a time code start point (first frame of a reel,
for example).
18. Variable Speed Override (VSO)
Used to varispeed the rate of the USD inter-
nal crystal-referenced clock (±699 cents; a
cent is one-hundredth of a semitone). VSO
is available at any positional reference set-
ting, but only when the clock reference is
Internal/VSO.