27-01-2019, 12:10 PM
(27-01-2019, 10:51 AM)`FRANK.C Wrote: One thing that jumps out is FM sound. Is this a 1930's standard?
I think that FM sound will be a problem. Not because the modulators cant do it but because the sound input pins of the modulators aren't used in Hedghog. But maybe this can be got around.
Frank
Hi Frank,
The standard was of 1947 and in use till March 1950 when Philips changed over to 625.
Philips took the 525/30 American standard and adopted it to 567/25, and chose a 4.5 MHz sound to vision carrier distance.
Although Philips did mention 567 lines already in a 1937 document. But no specs and it could very well have been AM sound and positive video modulation at the time. The applicable receiver was intended for 405 and used for demos across Europe in the Philips "Television Caravane" and was described as adaptable to 567. So I think that FM sound was not used at the time.
Unfortunately I have no pre-war Philips TV set in my little collection
(That would be even more fabulous than your magnificent standards converter!)
I suppose I can easily hard-wire the relevant pins of the modulator IC(s) to wherever it is needed, and cut any not-required connections.
Baseband video conversion is the most important of course, but it would be nice to have RF output as well.
Jac
