Tektronix Grass Valley 4000, Installation And Service

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Signal Processor Frame
DSK Mix/Wipe Module Set (Slot A16)
Generates the Wipes, Mix, Program Output and preview for the DSK.
Inputs:
■
DSK Program Video and Key
■
DSK Preset Video and Key
■
DSK K1 Video and Key
■
DSK K2 Video and Key
Outputs:
■
DSK Program Video and Key
■
DSK Clean Feed or program key
■
DSK Preview
Processors Used:
■
HOS
Sync Generator Module (064801) (Slot A9)
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 oscillator can be switched between
13.5 MHz for normal operation and 18.0 MHz for extended definition 16 X 9 aspect
ratio.
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.