Video and DC Power by Coax
Video and DC Power by Coax
(OP)
For a remote placed camera I want to feed the dc Power also via the coax cable.
The simplest way to do this is using an capaitor to block the dc and adding an inductor to block the video.
My question is wat is the best value of both items.
At this moment I am using 1000nF blocking capacitor and 33uH inductor. The image of the camera is walking and i very disturbed.
It would be handy to have a schematic of a working system.
What am I doing wrong and what is the easiest way to solve this problem.
Eim
The simplest way to do this is using an capaitor to block the dc and adding an inductor to block the video.
My question is wat is the best value of both items.
At this moment I am using 1000nF blocking capacitor and 33uH inductor. The image of the camera is walking and i very disturbed.
It would be handy to have a schematic of a working system.
What am I doing wrong and what is the easiest way to solve this problem.
Eim





RE: Video and DC Power by Coax
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Video and DC Power by Coax
You'll need to confirm the DC drop through the system to your camera.
Such DC Injectors and DC Blocks for composite video should be available for purchase. How much Googling have you done already?
RE: Video and DC Power by Coax
The vertical sync is about 60 Hz, and you'll need to pass enough of that to keep your monitor (or whatever is receiving the signal) happy. Circuits are available to help reconstruct the sync information.
Also, the absolute DC level is important, and many circuits and chips are available to reconstruct that.
Check out chips from National or Maxim and others. They have some good information and apps notes.
Another way to go, but with some loss of video quality, is to modulate the baseband to RF. (Cheap $10 modulators are available to convert baseband video to channel 3 ot 4.) The RF is much easier to separate from the DC. Then just convert it back.