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Old 26th Jun 2020, 11:44 am   #42
Semir_DE
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Join Date: Jan 2019
Location: Heusenstamm, (Near Frankfurt am Main), Germany.
Posts: 49
Default Re: My 819 line French TV project

Dear All,

just quick update on this subject matter.

As I am also experimenting with the old German 441 line standard I decided to tinker a little bit with the modeline parameters.

I found a very useful web site that allows you to tweak an existing modeline and will show you the timings of h-sync, v rate etc.

I started out with the 405 modeline I had and changed the line count and other items until I had the required timing. Here is a modeline that will generate the 441 line format:

Modeline "656x383" 8.82 656 665 744 800 383 383 391 441 -hsync +vsync Interlace

Again due to way my adapter processes the syncs the vsync is positive, for a simple adapter this should be changed to -vsync.

This modeline generates a vertical timing that is spot on, only h frequencies are slightly higher at 11.030kc instead of the 11,025 as defined by the standard.

Unfortunately I do not have a real 441 line TV (yet) but I have modified some older surveillance monitors to run on 441 and they work very nicely with my modeline signals. Also UK 405 sets can be used with this signal if the h-hold is adjusted to accommodate the higher horizontal frequency.

If anybody here has a 441 set I would be interested to know if this works on yours. As a modulator any 405 line modulator should work, especially the simple designs with LC tanks should be easy to modify to output the required frequencies.

Cheers

Semir
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