Question about sync and interlacing
pedward
Posts: 1,642
I have a Sony CPD-9000 monitor that has been sitting around for a bit. It's a 9 inch high quality trinitron CRT with a stated res of 640x240 and has a multiple input mode for analog RGB, 3 bit and 4 bit digital (CGA).
The specs state the sync is .3v p-p composite for analog mode, on the hsync input. How exactly does this work? The timing diagram shows the hsync and vsync timings for an entire field, but since they overlap I wonder how it's supposed to work.
Also about interlacing, do NTSC displays retrace exactly the same spot on the phosphor for each field, or are the fields slightly offset and thus the phosphor persistence gives the illusion of higher resolution?
This CPD-9000 is basically an old analog monitor that roughly mirrors NTSC very closely, the line period is 63.5us and the field period is 16.6ms, corresponding to 60fps at 640x240. I'm wondering if I can hybrid the NTSC and VGA drivers together to drive this display in analog mode.
This has value for the Commodore 1084s display too, since they are essentially identical in this way.
The specs state the sync is .3v p-p composite for analog mode, on the hsync input. How exactly does this work? The timing diagram shows the hsync and vsync timings for an entire field, but since they overlap I wonder how it's supposed to work.
Also about interlacing, do NTSC displays retrace exactly the same spot on the phosphor for each field, or are the fields slightly offset and thus the phosphor persistence gives the illusion of higher resolution?
This CPD-9000 is basically an old analog monitor that roughly mirrors NTSC very closely, the line period is 63.5us and the field period is 16.6ms, corresponding to 60fps at 640x240. I'm wondering if I can hybrid the NTSC and VGA drivers together to drive this display in analog mode.
This has value for the Commodore 1084s display too, since they are essentially identical in this way.
Comments
Does it have separate hsync and vsync or just horizontal? Some of those kinds of displays will also take sync on green, meaning you might just be able to send the whole signal on green; otherwise, I would try just outputting the sync pulses from the VGA on the hsync input, all else on the RGB channels.