When I was working in Philips as a service engineer,I have sucessfuly
converted NTSC to PAL using the highend box salveged from old
33FL1880 TV's .The job of the high end box is to convert 50Hz field
refresh to 100Hz, inside you can see a 8052 controlling the write refresh
freq:13.5Mhz and read refresh 27Mhz pll's,of the RGB memory.
I used this module to convert NTSC Laser Disks,to PAL to record
on to a VCR it was back in 1993.
But for any experimenters I recomment to experiment on this modules
If they can find one of these highend box,many old 33inch TV's uses
this ,I persume in the US it will be used to convert 60 t0 120Hz.
Construct one composite sync generator ,I used the Hitachi HA1365
(I do not remember exactly the hitachi IC no ) ,I still have this module
with me . If any one could see the circuit (service manual) it is very
intresting and easy to understand the full concept,
There is a write clock (which is the horizontal freq -in my case 15750
NTSC used to generate the write clock of 13.5 Mhz ) for the write refresh it is the 60Hz from the vertical freq of the in put.
The read clock is a 27Mhz which is generated in the highend box(which also need a little trimming for a stable pix )
and the read refresh is the50 Hz which I took from the sync generator.
The out put RGB I used a Mortorla IC to combine to composite video.
The out put RGB need a little amplification.
Anybody intrested in this concept try to get a old highend box and
start experimenting,at least try to get the circuit of this conversion box
It is very explicit and quite intresting .The the real system converter
also worlks the same way.
Any body have any query please write in this forum ,I would lilke to answer .
Jay
their questions.