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#1
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The Digi Key coils tended to have a lower DC resistance than the originals- Putting them in series until I had the correct inductance value worked for me.
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KStanki@aol.com |
#2
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I want to modify what I posted above.
To look for quadrature distortion, you can look at the I demodulator output during the Q (green/violet and violet/green) transitions, and vice versa. If the source has wideband Q, it will cause quadrature distortion in the I demodulator, even in a perfect receiver. This could be a lot of what you are seeing in the transitions between green and violet (but there could also be ringing in the Q signal itself). NTSC screwed up the Q channel color encoder specs by not including a 920 kHz trap in Q baseband (or a lower sideband trap following the Q modulator), so even with a perfect receiver, it is possible to get quadrature crosstalk from Q into I if the lower Q sideband is not strongly suppressed at the encoder. (The upper Q [and I] sideband is always strongly suppressed by sound traps.) Last edited by old_tv_nut; 01-26-2024 at 01:45 PM. |
#3
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I reckoned the effort RCA initially went to in the CT100 was to minimize quadrature crosstalk. With the inductances I mad as described, I was able to achieve these response curves which yielded a picture free from ringing yet obtained opptimal chrman resolution.
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