Merging / splitting DC/AC signals sharing a conductor...

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Dean Huster
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Post by Dean Huster » Tue Dec 25, 2007 9:16 am

I seem to recall that in television sets, DC-coupled amplifiers were always so problematic that they were rarely used. So, especially in the older analog, all-discrete sets, they used AC-coupled amplifiers for the video and a DC restorer circuit to shift the black video level where it belonged.

Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).


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Post by Droidwerkz » Sun Jan 13, 2008 5:32 am

what about a diplexer of the type used for running a tv signal over the same cable as powered lnb's in satellite systems? there is a dc power passing i/o side and a dc blocking ac passing side and they are readily available from satellite dish installers, they use a standard 75 ohm connection for both i/o's and pass ntsc through the non power passing side. you can draw your dc from the other i/o.

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