#31
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Lets not forget the fact that these are all high impedance circuits. You could just make an "unun" transformer. So you have 1v p-p composite in, and you need 10v p-p out? 1:10 matching transformer. Phase inversion is easy if you use a 1:1 isolation transformer (There are many made just for video.) and flip the output phase. You can also combine both. Invert the phase and derive 5v p-p baseband via a swapped output 1:5 ratio unun.
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#32
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That's a good idea, and I guess that raises another question that I hadn't thought of. Does the composite input need to have a 50 ohm termination? I haven't worked with video inputs very much, so I'm not sure what would work best. The unun transformer is a good idea, it might also be useful for a hot chassis set. Without some form of isolation, I don't think it's a good idea to add such an input to a hot chassis set.
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#33
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#34
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#35
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Quote:
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"When resistors increase in value, they're worthless" -Dave G |
Audiokarma |
#36
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That will work to create composite video that will have minimal cross luma into chroma errors in a notch filter color TV set. If the TV set in question is a notch filter set, the luma bandwidth that you see on the CRT screen is low pass filtered to avoid the appearance of the chroma subcarrier (a crawling fine grain checkerboard pattern atop highly colored areas of the image). True S video would produce about twice the resolution than the above composite video maker. But this composite video lets you not need to dig deeply inside the set's color circuits.
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