Chapter 11, SMPTE, Sync and Offset
ALESIS M20 REFERENCE MANUAL 1.06 11-5
11.6B SET SMPTE CHASE MODE (PAGE 2)
There are two chase modes: Frame-Lock (default) and Lock/Release (i.e., Lock and Release
to clock). Chase must be enabled.
The Down Arrow button or keypad button 0 selects Frame-Lock. With Frame-Lock mode,
the M20 will relocate to incoming time code if it does not match the current tape location.
The Up Arrow button or any keypad button greater than 0 selects Lock/Release. In
Lock/Release, the M20 references the incoming time code location to establish a lock. Once
locked, it ignores the time code data and follows the selected external clock source to
maintain lock.
Definition of Lock/Release mode: In Lock/Release, if the incoming time code stops for
more than the flywheel amount (section 11.6c), is running but not advancing its
frame numbers, starts counting frames backwards, or begins to advance at a non-
play speed, the M20 will stop playing and attempt to chase to the time code location.
If the time code is advancing forward but has a discontinuity, the M20 will continue
to play without attempting to chase to the new time code location. Lock and release
mode is a more “forgiving” mode in difficult time code applications where the
master code has dropouts or jumps from one type to another.
11.6C SET FLYWHEEL DURATION (PAGE 3)
This parameter selects the maximum number of invalid or missing time code frames that will
be ignored (up to 150 maximum). In Frame-Lock chase mode, the M20 keeps playing for the
flywheel time as if valid time code was present, then chases when valid time code data
reappears. In Lock/Release chase mode, flywheel sets the amount of time that the M20 will
continue to play in the absence of incoming time code before stopping the tape.
Use the Up/Down buttons, or enter a 3-digit number with the keypad (leading zeroes must
be entered).
11.6D PARK AHEAD (PAGE 4)
The M20 can park tape ahead of the last valid time code input, up to 59:29 (seconds/frames).
Default is 00:00 (tape does not park ahead). The Park Ahead parameter is available to make
lockup times shorter in situations where the master time code source drops out or drifts for a
few seconds as it stops and starts (for example, when a VTR disengages).
Operation You press… You see…
Select field to edit Left/Right Arrow
buttons to scroll to
desired field
Cursor under selected
field
Change numeric field
value Enter two-digit number
from keypad (leading
zeroes must be entered)
or use Up/Down buttons
Your entry replaces
current field value
Exit Park Ahead setup Edit button or any other
Edit Group button Display leaves Park
Ahead function