Grass Valley 8981FS - Manual (Page 36)

30 8981FS Instruction Manual
8981FS Digital Frame Synchronizer Module
27 MHz clock and the timing of a half-frame rate pulse feeding the read
control logic. This clock and pulse is produced by the genlock and output
timing control logic.
Genlock and Output Timing
The genlock and output timing control block can either lock its outputs to
an analog color black reference input or to timing pulses from the write
control logic. The analog video reference is used in the frame synchronizer
operating mode. The signals from the write logic are used in the fixed delay
operating mode.
Video Output
Video data from the frame memory output feeds the output signal pro-
cessor circuits. This circuit can vary the signal levels, insert video black,
insert new digital timing sequences (EAV/SAV), and insert new EDH
checkwords. The video from the output signal processor feeds a serializer
and line driver that drives the module’s four output connectors.
Micro-Controller
A micro-controller is used to control all functional blocks and to store and
retrieve user-stored or factory preset operating parameters.
Audio Delay
The time that elapses between writing video into memory and reading it
back out is measured by logic which produces a serial data stream that
carries this time delay information. This signal feeds two output BNC con-
nectors for use by other Grass Valley Group modules that can delay audio
to match the video delay produced by this module.