
22
5.6.5 Computer Driven External Offset Control:
If this option is installed, the internal analog offset control potentiometer is removed and the
offset control function is performed by feeding a variable DC voltage to the camera via DB-37
connector (pin 18 is used for the offset control DC voltage). This control voltage may be
generated from any external source, including (but not limited to) a Digital-to-Analog converter
on an Image Processor or computer peripheral board. The range of operation of the External
Offset function is 0 to 14 IRE units from 2V to 3.125V respectively. It has a linear response
between 2V and 3.125V (see curve below).
5.6.5.1 Default:
The camera defaults to max. offset if the external "black box" is not plugged into a camera that
has been modified for External Offset Control.
5.6.5.2 Linear Range of Control:
Care should be taken to keep the control voltage in the linear range between 2V and 3.125V;
outside this range, the offset defaults to certain "preset" levels in a discontinuous manner !
5.6.5.3 RS-170 Pedestal:
The RS-170 standard specifies a "setup" or "pedestal" of 7.5 IRE units. As shown on the above
curve, this is obtained with a control voltage of around 2.6V (actual settings will vary slightly from
unit to unit).
Analog Video Offset vs. Control Voltage
0
2
4
6
8
10
12
14
2
2.125
2.25
2.375
2.5
2.625
2.75
2.875
3
3.125
Control Voltage (volts)
Analog Video Offset (IRE Units)
RS-170 standard offset = 7.5 IRE
Figure 5-9: External Offset Control Curve
Содержание DigitEyes Series
Страница 14: ...9 Figure 4 3 TC 245 Gate Level Drawing Texas Instruments 1994 ...
Страница 61: ...56 12 Appendix D Camera Mechanical Drawings Figure 12 1 Camera Mechanical Drawings ...
Страница 63: ...58 Figure 13 2 Camera Noise Spectrum Min Gain Bandwidth 10kHz to 4 2MHz ...
Страница 64: ...59 Figure 13 3 Camera Noise Spectrum Max Gain Bandwidth 100kHz to 4 2Mhz ...
Страница 65: ...60 Figure 13 4 Camera Noise Spectrum Max Gain Bandwidth 10kHz to full ...