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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 22nd Jun 2020, 10:56 pm   #41
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,

Here are the mode lines I have currently in my ".profile" file on my Mint Linux system.

one more I am planning to test is a version for 441 lines.

This is all running very nicely on a fan-less Nvidia N710 PCI Express 16 graphics card.

xrandr --newmode "819" 29.3203 1152 1168 1240 1432 738 744 745 819 -hsync +vsync interlace
xrandr --addmode VGA-1 819

xrandr --newmode "405" 8.10 664 680 752 800 377 378 385 405 -hsync +vsync interlace
xrandr --addmode VGA-1 405

xrandr --newmode "PAL" 13.875 720 741 806 888 576 581 586 625 interlace -hsync +vsync
xrandr --addmode VGA-1 PAL

xrandr --newmode "PAL-SQP" 14.750 768 790 859 944 576 581 586 625 interlace -hsync +vsync
xrandr --addmode VGA-1 PAL-SQP

xrandr --newmode "NTSC" 13.846 720 744 809 880 480 488 494 525 interlace -hsync +vsync
xrandr --addmode VGA-1 NTSC

Please take note that this configuration uses a positive vsync and a negative hsync. This is owed to the fact that I am using a single XOR gate to generate a somewhat compliant vertical sync with h-serrations. If you intend to use the simple resistor adder network for generating the composite signal please change the "+vsync" in each modeline to "-vsync"

you can find the .profile file I'm using in the attached zip file.

Cheers

Semir
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File Type: zip profile_look_for_it_in_home_folder.zip (757 Bytes, 10 views)
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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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