Converting RGB --> VGA
Backgroud:
Modern PC's uses high resolution VGA/SGVA/XGA and many other hybrid form of any of these while the TI-99/4A/Geneve's/Many MSX' that are all based on the antique TMS9918 or one of its successors uses RF modulation, composite video or RGB video.
The modern PC's often use horizontal scan frequencies starting at 31.25 KHz (Europe) and 31.50 Khz (US) and scaling those frequencies up to over the 160 KHz thesedays while our old 'video' based signals that are fully compatible with PAL/NTSC specifications, will not scale up above the 15.625 KHz for PAL systems and 15.750 KHz for NTSC systems.
You see the similarity? 15.625 KHz for PAL x 2 = 31.25 KHz VGA in Europe and 15.750 KHz for NTSC (17.734 KHz to be more precise) x 2 = 31.50 KHz VGA in the US. Actually many modern PC VGA compatible monitors accepts horizontal input frequencies starting at 31 KHz or even 30 KHz.
So the minor differences in the specifications shouldn't pose a problem for the monitors. What will be a challenge is to convert PAL/NTSC frequencies to VGA frequencies.
And if we over come this problem the next one arises, the scan lines... 'TBD'.
Technical possibilities:
- Information on how to connect the Geneve RGB to a SCART enabled device.
- Information on how to connect any RGB device to a SCART enabled device. (Will come soon).
- Converting 15 KHz RGB Video signal to 15 KHz RGB VGA signal. (Will come soon).
- Video double scan solution for Converting 15 KHz RGB Video signal to 31.50 KHz RGB VGA signals. (Will come soon).
Comments, ideas or suggestions:
Can be sent to: ti99@collosumus_NOSPAM_.net, please remove the _NOSPAM_ from the e-mail address. You can't be to careful with spam these days.
Last update: 05/14/2003.