Time Code Tutorial, Chapter 17

17-2 ALESIS M20 REFERENCE MANUAL 1.06

9 Press INT GEN or TC INPUT to stop the time code generator.
The variations of INT GEN should be easy to explore from this point on. Using different
options in steps 2, 3, and 4 above, you could generate time code that’s in lock-step with the
ABS time of the M20, that starts from the TC track reference, or only generates time code
when the M20 itself has a tape in it and is running.
17.2 SYNCHRONIZING WITHOUT A T/C TRACK
Now that you have a master tape with time code, let’s get the M20 to chase and lock to the master
tape. The built-in ABS time code of the M20 may be used as a Chase Reference, without having to
pre-stripe a tape’s TC track. ABS Time is the sample-accurate time code written onto each ADAT
tape during the FORMAT process. It is used as the ultimate time reference for the system. This is
the time that shows in the 4-digit display of any ADAT ever built.
Using ABS as the Chase Reference is particularly useful in live recording when you don’t
have time to pre-stripe a tape. You can even synchronize while formatting, a unique
advantage of the ADAT format.
ADAT's internal time code is more accurate than conventional SMPTE time code. The M20 can
translate this ABS Time into any speed or type of SMPTE time code in order to synchronize with
non-ADAT masters or slaves. Since ABS Time covers only a 40 to 60-minute span, and SMPTE
covers a 24-hour day, the M20 was designed so it can translate any point of ADAT’s ABS Time to
any desired point on the 24-hour SMPTE/EBU time code clock.
If you use the default settings of the M20, the zero point of every ADAT tape will translate to
"midnight" (00 hours, 00 minutes, 00 seconds, 00 frames) SMPTE. If you need to change this
"zero-to-zero" relationship between ADAT's ABS Time and incoming/outgoing SMPTE time
code, you change either the INT GEN ABS offset or the SMPTE Chase offset.
Set SMPTE offset, frame-lock or lock & release, flywheel, park ahead
Chase = Abs time
Clock source: video (or word, or optical, etc.)
Make connections of SMPTE and clock source
Set Reference Counter to SMPTE IN, Tape Counter to ABS or SMPTE