Chapter 11, SMPTE, Sync and Offset

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

Cursor under selected

 

buttons to scroll to

field

 

desired field

 

Change numeric field

Enter two-digit number

Your entry replaces

value

from keypad (leading

current field value

 

zeroes must be entered)

 

 

or use Up/Down buttons

 

Exit Park Ahead setup

Edit button or any other

Display leaves Park

 

Edit Group button

Ahead function

ALESIS M20 REFERENCE MANUAL 1.06

11-5

Page 69
Image 69
Alesis ALESIS M20 owner manual 11.6B SET Smpte Chase Mode, 11.6C SET Flywheel Duration, 11.6D Park Ahead, 11-5