I picked up a Sony 9" black and white monitor yesterday. It is a SSM-930 with 750 lines of horizontal resolution. It has a "DC clamp" switch which has something to do with stabilizing black the level. What is this switch used for?
Tom Dressel
Video Monitor Questions
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Richard Hull
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Re: Video Monitor Questions
The monitor you have is probably an old medical or scientific application monitor and the DC clamp warrants that the black level will not exceed certain levels. It is, in effect, a contrast limiter. Normally, video black is not pitch black. A full video signal is listed at 100IRE units. video black is normally spec'd at 7.5IRE. Thus, for broadcasters, video black is really a white level of 7.5IRE. Medical applications are not broadcast applications and the blacks and tonal ranges need to be controlled and sometimes their ranges extended or limited (clamped). This switch warrants that the DC position of the video waveform (black level) is fixed. Regardless, it is unimportant for your purposes. Adjust the switch and contrast and brightness controls for best image from the fusor to your eye. I have found that raising the black level will actually increase the tonal range a bit on an otherwise stark image. It is more of a matter of pleasing your own taste mixed with getting the most information you can from the image.
I have posted on this before on the old list regarding recording the image from video, boosting contrast, extending tonal ranges and the like.
Richard Hull
I have posted on this before on the old list regarding recording the image from video, boosting contrast, extending tonal ranges and the like.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Tom Dressel
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Re: Video Monitor Questions
The monitor is actually relatively new made in May of 98, and designed as a security camera monitor. Turning on the DC clamp does have the effect of decreasing the contrast.
Tom Dressel
Tom Dressel