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Old 3rd Mar 2018, 5:09 am   #15
Argus25
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Modeline problem

Since it appears that the modeline system produces good video picture data, but has unsatisfactory sync, then a reasonable solution would be to simply make a new sync generator circuit, probably just synchronised with resets, and re-insert a good sync to the output video signal.

There is really no good reason why the interlace should be problematic, provided the sync signal has the timing that there is an exact a half line difference at the leading edge of the vertical sync . If it does have issues on the actual set even with a correct signal and there is poor interlace, this merely suggests that the frame osc in the TV is being inadvertently triggered by line pulses which should not happen if the interlace filter has the correct proportions/time constant.
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