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Old 19 October 2006, 13:42   #12
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Join Date: Jan 2004
Location: Oxford
Posts: 11,741
Designing a scandoubler is VERY VERY easy. Actually being arsed to make one that is another thing altogether.

converted the output to a digital signal using a 3 channel ADC you could then store the data to RAM on change of the timing pulse resulting in a frame (line) being in the devices ram.
Yup. You need a DAC on the other side of the RAM to convert back to Analog for the monitor. You can use R2R ladders instead of a DAC but make sure you get your values right.

I wonder how well flicker fixing would go if you read line 1 then line 2 while writing line 1 and so on, this would result in only a small a ram being required.
The TV sends lines interlaced. That is all the odd lines followed by all the even ones i.e. 1, 3, 5, ... 575, 2, 4, 6.... 576. You have to buffer lines 1-575 (288 lines) if you want to then output them as progressive (flicker fixed) 1,2,3,4 etc.

duel ported ram could be used so that it could be written to on odd cycles and read from on even ones.
You dont need a dual-port RAM if you are going to read and write on alternate clock cycles. Because you are accessing sequential locations you just make the RAM 2x as wide and read/write two pixels at once on alternate clock cyles.

I might get a silver conductive track pen tomorrow so I can draw the tracks.
Watch your impedance on the analog signals.

Last edited by alexh; 19 October 2006 at 13:47.
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