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Switcher Module Description
Sync Generator Module (064801) (Slot A10)
The basic functions of the Sync Generator Module are:
■ Use the input reference video to lock the switcher
■ Generate sync pulses for the other modules in the system
■ Generate clocks for the other modules in the system
■ Generate “Sync Edge” pulse for analog input alignment
The input is the analog reference video signal. This signal is brought in as
a differential video signal from the Communications I/O Module at the
rear of the frame. The video is filtered, then sync is stripped off. The sync
is used to lock a 13.5 MHz phase-locked loop. The 13.5 MHz signal is used
to lock a four times 13.5 clock from which all sync pulses are derived.
The two clocks generated on this module are “system clock” and
“multiplex clock” which is twice the frequency of “system clock.” These
clocks have a separate driver for each module. The clock outputs are
differential positive ECL level. The multiplex clock is used on the modules
to multiplex and demultiplex the video signals. The system clock is used to
clock the video through the system.
The system sync pulses are a TTL level and are generated from the four
times 13.5MHz phase lock loop. There are two separate generators, one for
the vertical rate signals and one for the horizontal rate signals. The sync
pulses have drivers that feed four or five modules.
The “dither” mode line is controlled on the Sync Generator Module
through the VID interface.
Switches:
■ Clock Frequency 13.5 MHz
■ Field Rate 50 Hz or 60 Hz select
■ Tally Control Module reset
■ Horizontal timing (three switches)