Model 5010 Time Code Master Manual
TECHNICAL DESCRIPTION
Revision 3.1.1
Page
6-3
6.3.2. Calibrating the VITC Generator Keyer
(models 5010-VITC and 5010-VITC-24 only)
To calibrate the VITC Generator’s video keyer, connect the colour bars from your sync generator to
the VITC Gen Video input of the 5010-VITC or 5010-VITC-24 and to channel A of your oscilloscope.
Connect the video output to channel B of your scope and terminate it. Adjust the
VGAIN
trimpot R122
on 7700STM board (GAIN trimpot VR2 on 5235 sub board) so that the output amplitude matches the
input. Adjust the
VTC LVL
trimpot R117 on the 7700STM board (LEVEL trimpot VR1 on 5235 sub
board) so that the inserted VITC/characters are approximately 550 millivolts above video black level.
6.3.3. Calibrating the Character Generator
To calibrate the video keyer, connect the colour bars from your sync generator to the Reader Video
input loop of the model 5010 and to channel A of your oscilloscope and terminate it. Connect the
character generator video output of the model 5010 to channel B of your scope and terminate it.
Adjust the
GAIN A
trimpot R120 for VITC output A or
GAIN B
trimpot R173 for VITC output B (GAIN
trimpot VR3 on 5200 board) so that the output amplitude matches the input. Adjust the
CHR LVL
trimpot R211 on the 7700STM board (CHAR LEVEL trimpot VR2 on 5200 board) so that the inserted
characters are approximately at the peak white video level.
The starting position of the characters at the left of the screen is adjusted by trimpot R105 on the
7700STM board (VR1 on the 5200 board). The horizontal character size is set in software using the
HORIZONTAL SIZE menu item on the Engineering Setup menu.
6.3.4. Calibrating the Colour Frame Detection Circuit
Calibration of the colour frame detector is accomplished in software. Separate calibration values are
maintained in the 5010’s nonvolatile memory for PAL and NTSC. The colour frame circuitry is
calibrated at the factory and should not require any field calibration. If you do need to calibrate the
colour frame detector, use the following procedure. To enable adjustment of the NOVPOT, you need
to set DIP switch 1 on the main circuit board to the On (Closed) position. The front panel display will
show a display similar to:
COLFRM POT N : 10
for
NTSC
or
COLFRM POT P : 10
for
PAL
When this message is displayed, the rightmost digits of the display indicate the value of the digital
potentiometer (NOVPOT) used to calibrate the colour framer. The numbers do not have any absolute
meaning, but are only a reference used in calibration. Use the
Ï
key to adjust the NOVPOT value up
and the
Ð
key to adjust the NOVPOT value down.
The generator REF VIDEO input must be connected to an RS-170-A NTSC or an 8 field PAL video
source, and properly terminated. The unit must also be set up to operate in the colour frame mode.
This is accomplished by using the
COLOUR FRAME
menu item of the Setup menus. Select
4 FIELD
for NTSC or
8 FIELD
for PAL.
You will need a sync pulse generator with a colour field #1 identification pulse output and a dual
channel oscilloscope to perform the calibration.
1. Display the colour field #1 ID pulse from your sync generator on channel A of your oscilloscope.
Set up the time base to show two pulses (usually 20 msec / div.). Set up your oscilloscope to
trigger from channel A.
