03-06-2019, 07:45 PM
(03-06-2019, 10:24 AM)ppppenguin Wrote:(02-06-2019, 06:22 PM)Semir_DE Wrote: Apart from these two valve projects I also have built an AM TX sing a TBA520 PAL decoder chip as a balanced modulator and oscillator.The TBA520 can also be used as a PAL encoder. Labgear made a colour bar generator that used it.
Yeah I know, those chips can be quite useful. In the 1980s I had built a PAL pattern generator using about 50 TTL chips.
The sync generator in that project was the one published in Television magazine in the late 70s.
For the PAL encoder I used the successor of the TBA520 the TBA990. When driven with a low carrier signal level this worked very well. This was way before dedicated ICs like the Sony CX22017 had become available to me as a hobbyist...
