Grass Valley 8981FS - Manual (Page 18)

12 8981FS Instruction Manual
8981FS Digital Frame Synchronizer Module
Input Signal EDH Detection
The module monitors its video input signal for EDH (Error Detection and
Handling) checkwords. If checkwords are present, active picture only or
full field input signal errors will cause the front of module FAULT indicator
to illuminate briefly each time an error is detected. The EDH Error Mode
control function determines whether ACTIVE PICTURE or FULL FIELD
errors will cause the indicator to illuminate. (See
Table 3 on page 15 , Func-
tion Switch positions 6, Bank 1) New EDH checkwords per SMPTE RP165
are always inserted into the module output signal. The EDH Error Mode
setting will have no effect on the new EDH checkwords inserted at the
module output.
Manual Freeze and GPI
Freeze mode can be manually initiated when operating either as a frame
sync or fixed delay. It can be used to provide a frame or field grab for pro-
duction applications. Freeze can be triggered using the GPI input BNC con-
nector or using the 8900 series remote control system. When operating in
delay mode, a stable input signal must continue to be present to produce a
stable freeze output.
The selection of which type of freeze (Frame, Field 1, or Field 2) can be
made via the Frame/Field Select and F1/F2 control functions. (See
Table 3
on page 15 , Function Switch position A and B, Bank 1).
The GPI connection is a dual function connection. It can be used as both an
output to drive a remote LED to indicate when the module is in the freeze
mode and as an input that can control the freeze mode (see GPI Freeze
Trigger Circuits
on page 25 for control wiring required to use the GPI con-
nector).
The GPI control input must be ENABLED using the Freeze GPI mode set-
ting. (See
Table 3 on page 15 , Function Switch position B, Bank 2).
SEE GPI Freeze Trigger Circuits on page 25 for more information on GPI
circuit design and operation.
Signal Processing — Offset and Gain
If video signal levels need to be adjusted, the video signal level controls
must be activated by setting the Video Signal Levels mode setting to VARI-
ABLE. (See
Table 3 on page 15 , Function Switch positions E, Bank 1) If this
mode setting is in the UNITY position, the video signal levels will be fixed
at unity gain and with no black level offset. If VARIABLE is selected, offset
and gain adjustments can be made for each component video channel— Y,
B-Y, and R-Y. Offsets are adjustable ±31 least significant bits (10-bit video).