162
Expression Show Control System
Internal clock mode
During normal operation, the
ESCS processor continuously compares incoming
SMPTE time code with time data from its own internal clock. If the
ESCS
detects variations of plus or minus two seconds, it will automatically adjust the
execution of cues to resynchronize itself with the SMPTE time code it is receiv-
ing. If it detects variations of more than two seconds, the
ESCS automatically
switches to internal clock mode. In internal clock mode, the
ESCS executes cues
based on its own internal clock. It then resynchronizes to the new SMPTE time.
This takes place when it receives 30 consecutive, valid SMPTE frames. If the
flow of SMPTE code to the
ESCS is stopped, the ESCS will continue to run cues
based on its own internal clock until SMPTE input is restored.
