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6.2.
DIAGNOSTIC LEDs
TECHNICAL DESCRIPTION
The module contains all the necessary video processing circuits and
therefore, requires no external signals other than the video signal itself.
Recovered VITC data is transferred to the companion LTC reader module
for validation and further processing. The MCU presents valid data from
whichever source it selects, to the 615 and 631 modules via the EV-COM
bus.
The 631 module is comprised of a 6120 Base Processor board with a 6231
Character Generator Submodule.
provides white or black characters keyed into the video with or without a
contrasting background. Character size and raster position are software
selectable. The character display may be used to show generator time,
user bits, film edge codes (KeyKode), or absolute frames from a reference.
Each of the windows can be turned on and off and positioned independent
of each other.
When displaying time recovered from a VITC source, the field number
sequence will be displayed to the right of the frames display. When the
data being read was recorded in the non colour frame mode the field
number sequence will be 1,2,1, etc. (1,2,3,4,1, etc. for PAL). When the
reader data was recorded in the colour frame mode, the field number
sequence will be 1,2,3,4,1, etc. (1,2,3,4,5,6,7,8,1, etc. for PAL).
When displaying film edge numbers, a telecine lock flag indicates when the
4025 has properly locked on to the telecine transfer sequence at Play
speed. In 24 frames per second transfers, a film sequence character is
displayed, indicating where in the 3/2 sequence a particular frame belongs.
The character inserter is also used for the on Screen Programming menus
which are used to set up the various operational modes of the 4025.
Each of the main circuit cards inside the 4025 has one or more diagnostic
LED indicators to aid in troubleshooting, should it become necessary.
These LEDs are only visible with the front panel removed.
6.2.1. Power Supply LEDs
These appear to the extreme left of the interior of the 4025. From front to
back they indicate the presence of +8V,-8V and +9V (which runs the 5V
regulators for each board).
6.2.2. Reader LEDs`
The LTC/VITC reader module pair is located in the left slot of the 4025.
There are two LEDs located at the front of this module.
LTC
The left LED indicates LTC is being read.
VITC
The right LED indicates VITC timecode being read.
Model 4025 Film Footage Encoder Manual
The 631 video character inserter
Page 6-3
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