V6402, V6404, V6406, V6408
and V6418 HD converters
HU-V6402&4&6&8&18
51
4
CALIBRATION
This section describes how to calibrate the unit as it is done in the factory. The units do not contain any
potentiometers, but like most equipment with analogue parts still needs to be calibrated. Normally this
calibration is done in the factory and should not need to be repeated in the field but this section describes
the procedure and is included for completeness.
High quality, calibrated test equipment should be used for this calibration. Note that it is not possible to
return to the pre-calibration settings other than by making a note of the values and re-entering them.
4.1
Set-Up
There is a separate Main Level Menu for Calibration and this should be used throughout. The first sub-
level menu is Cal Mode, which can be used to turn calibration ON:
CALIB
Cal Mode
Cal Off
Cal On
The calibration mode must be turned ON before any parameter can be adjusted. The calibration mode will
be turned OFF in one of four ways:
1. Manually on the
CALIB
:
Cal Mode
menu
2. By going up to the Top Level Menu
3. By re-powering the unit.
4. By letting the display timeout and go to sleep mode.
When the calibration mode is ON then the unit will automatically set up the required conditions in the unit
as you enter each sub-menu. For example, if you go into the CntrFreq sub-menu, the unit will
automatically go into free run. For obvious reasons this should not be done on a unit that is being used On
Air.
4.2
Free-Run Frequency
There is a voltage controlled crystal oscillator, which is usually locked to the external video reference or to
the input video. However if there is no input or reference then it will free-run and this free running
frequency should be set. The oscillator is not accurate enough to be used as a frequency reference, but
nevertheless, should be set close to the ideal so that any succeeding SDI equipment will be able to lock to
its output, and so that when in free run it will only drift slowly away from its starting reference.
To calibrate the frequency set the unit into Free Run by turning Cal Mode ON and selecting the CntrFreq
sub-menu.
CALIB
Cal Mode
Cal On
Now compare the output picture movement on a monitor with an accurate external reference and adjust
the frequency accordingly.
CALIB
CntrFreq
Range is –127 to +128
The setting is stored on the unit in non-volatile memory, and should not need regular adjustment..
V6406
V6408
V6418
V6404
V6402
