The circuit is based on AD725 encoder, and the proto board is functioning relatively well. Here're the pics:

NTSC mode: enter image description here

PAL mode: enter image description here

Circuit detects PAL or NTSC mode using MCU, and performs automatic switching to the respective mode of operation and input clock.

As you can see PAL output is left-aligned to the screen border. While there's software way to adjust horizontal position of the image, it would be great if, when changing the mode (50 Hz <-> 60 Hz) image would adjust automatically.

I searched for available information, and did not find anything specific other than theory on how video works. My initial idea is to delay some signal, but that would be delaying all color video signals relative to HSYNC in PAL mode which potentially leads to significant circuit complexity increase.

And also not sure if it is so simple - colors are timed together with SYNC, and encoder may extract wrong information from the color channels due to timing discrepancies (like I had with my original big problem).

Are there any simple ways to achieve the outcome in-circuit - have NTSC image as it is and PAL image shifted right several pixels?



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