Amiga pages in Savel site. Selfmade hardware (Genlock.)

GENLOCK

WARNING!: This hardware project is for very advanced people only! For absolute crazy ones! You must know how basic electronic parts work. You must know how to build PCB board. You must know how to solder SMD parts. I am warning you: You can kill your Amiga. This project will be tested on A500 and A1200 only. If I kill A500, I'll close this project for a long time. I don't have other Amiga to test.

Are you sure to continue?

Visit these pages for chip information Elantec semiconductor, Inc.. We will use some chipsets from them.
No more data. 1999.05.28

BASICS:
What is genlock? This is phase locked generator to synchronize computer to external sygnal. In this case to syncronize computer to external video. Why to synchronize? If you don't do this the subtitles will move all around the screen and in some cases you'll never get ANY video output. Why we need genlock? If we want to make titling mashine or just want to put your logo in the corner of TV/VIDEO program like all TV station do.

THEORY:
All computers use some oscilator to clock all other parts. Generaly it is crystal oscilator, or cristal oscilator and PLL. The clock must be high enough to make your computer work quickly and make output graphics elements small. Recent computers uses separate clock for Video and CPU. These computer are colled asynchronous. Old Amiga models without aditional CPU upgrade are not asynchronous. They use same clock for everything. Even A1200 is synchronous unless you add some accelerator.
Amiga's video subsystem uses one crystal oscilator placed on mainboard: 28.37516 MHz for PAL and 28.63638? MHz for NTSC. To use external clock, we need to produce this 28MHz from generic video signal and feed it to the Amiga computer. Where to feed? There is a special pin in Amiga video slot for this purpose. And one more pin to enable the external clock. All we need to take video signal, extract synchro pulses, generate 28MHz on these pulse base and feed it to the Amiga. Now, when Amiga is synchronized we need to mix Amiga's video with source video (There is a special KEY pin to do video overlay) and use this result as new video sygnal.

EXPERIMENTS:
1. Make external clock for your Amiga
Just take ~28MHz oscilator, 23 pin connector, switch and some PCB board and build this:

Still working? Good. BTW, if you take faster oscilator your Amiga will work quicker, but be carefull.

DETAILS:

EL4583C (Sync Separator, 50% Slice, S-H, Filter)
EL4585C (Horizontal Genlock, 8Fsc)
23 PIN MALE and FEMALE CONNECTORS (I used from old A1200 mother board)
Pasive elements: L, C, R
Some printed circuit boards: Base board and Beta genlock board. (It is portable document file, use any FREE PDF reader to look and print them)
Soldering instruments

no more information.... (1999.07.10)

This is photo of genlock under construction. Still collecting exact values of components and tuning the schematics.
(1999.07.23)

So, if you made it, now time to make mix device. All data is located in this Portable document file (pdf). At this point you can begin your video titling business... :)
No more data ... (1999.10.25)

SOFTWARE:
Any program using native Amiga screens. To enable "genlock mode" turn on genlock and external video source before turning Amiga on.

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