Avid Technology Digidesign USD, Руководство пользователя, Страница: 55 / 96

Chapter 4: Using the USD 51
MTC Generation/Regeneration
MTC (MIDI Time Code) is a serial digital
signal. In many ways, you can think of it as
an inaudible type of LTC, that can be used
by various MIDI devices.
MTC is available from the USD MTC Out
connector, which is a standard DIN-style 5-
pin female MIDI connector.
To use MTC, you’ll need to connect MTC
Out to a MIDI In connector of a device that
can recognize and use MTC. Typically, this
would be a console, sequencer, synthesizer
or sampler keyboard, a drum machine or
other device.
MTC Output and Idle Muting
MTC is normally output whenever LTC is
output. Whenever LTC output stops, USD
will continue to output MTC in bursts of
one frame every 200 milliseconds. This al-
lows any connected MIDI-reading device
to be continuously updated as to the posi-
tion of VITC or Bi-Phase (either of which
might be operating at slow or still speeds).
Thus, you can still use a connected MIDI
device for Auto-Spotting from VITC or Bi-
Phase.
Optionally, this constant output can be set
to mute when time code (LTC) is idle.
To mute idle-time MTC output from the front
panel:
1
Use the front panel Set, Up and Down
switches to display Idle MTC (IdLE 7C).
2
Press Set to display the current state (On
or Off).
3
Press Up or Down to toggle Idle MTC to
the Off setting.
4
Press Set again to exit and return USD to
its previous state.
To mute idle-time MTC output using
USD Setup:
1
Launch USD Setup.
2
Deselect the Idle MTC Enabled option.
Generating a Window Burn
The USD offers time code character genera-
tion (also known as window burn or dub-
bing). This superimposes onto a video sig-
nal a small area called a window dub (or
window burn, or time code window) that
displays time code in hours:minutes:sec-
onds:frames.
Idle MTC controls in USD Setup
Video image with window burn
Idle MTC, muted