26-01-2019, 12:39 PM
I noticed this post regarding German 441 line TV: https://www.vintage-radio.net/forum/show...ost1114281
It would be very simple to use the Hedghog hardware to do all that he's doing and much more besides. Including full conversion from 625 to 441. I doubt that any hardware mods would be needed, just changes to the VHDL.
Thinking even further, I can't see problems using the Hedghog hardware to convert to any other vintage standard. 405 line NTSC would depend on there being enough resources in the FPGA The decoder chip already provides Cb and Cr as well as Y. Just depends on having enough storage and processing to do the arithmetic. Deepending on how you do the sums, an NTSC coder isn't conceptually complex but does need several multiplications. The quadrature modulator needs 2 multipliers, though it may be possible to do it with one using multiplexing. Also need fixed coefft multipliers to get the U and V weighting. More may be needed to interpolate the U and V signals up to the output DAC frequency.
It would be very simple to use the Hedghog hardware to do all that he's doing and much more besides. Including full conversion from 625 to 441. I doubt that any hardware mods would be needed, just changes to the VHDL.
Thinking even further, I can't see problems using the Hedghog hardware to convert to any other vintage standard. 405 line NTSC would depend on there being enough resources in the FPGA The decoder chip already provides Cb and Cr as well as Y. Just depends on having enough storage and processing to do the arithmetic. Deepending on how you do the sums, an NTSC coder isn't conceptually complex but does need several multiplications. The quadrature modulator needs 2 multipliers, though it may be possible to do it with one using multiplexing. Also need fixed coefft multipliers to get the U and V weighting. More may be needed to interpolate the U and V signals up to the output DAC frequency.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
