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The idea is that looking at the effect on a simple square waveform fed through the video amps can tell you a lot about the types of frequency response you're getting. A marker generator seems more useful for helping to pinpoint problems in the IF or Chroma sections, whereas this method can specifically be employed for the video section. The video section is where my smearing issue is suspected. I've fed composite signal into the 1st vid amp and there is smearing. Signal fed into the 2nd amp shows no smearing on screen. The tuner AGC line may be playing a part, but I thought I'd start with testing signals around the 1st and 2nd vid amps. Note, I am unable to get snow on the screen without an RF input signal. Again I haven't figured out if the tuner has anything to do with my positive and negative smearing issue.
It may be worth trying, or perhaps I could just stick with something that can do a bar sweep, like a Sencore VA-48 and analyze the responses that way.
An Indian pattern was certainly available at the time of the article I referenced, but I don't think the second generation pattern generators were out yet, or at least not common.
Last edited by Jon1967us; 07-27-2021 at 12:16 AM.
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07-26-2021, 12:00 PM
Hybrid Mode
