If you want to build it from scratch 100% exactly to NTSC specification it is hard. The precise signal parameters were designed to make the receiver side synchronization (originally using tubes) simple not the sync generator. There is really a fair amount of slop in what a receiver will accept and still generate a stable video signal as transmission standards usually generate the most precise signal possible and design the receiver to accept the most imprecise signal while still giving acceptable performance.

Just like I remembered, one of my old design 8080/TTL S100 video graphics systems used something like Don Lancaster's composite video circuit to generate the required signals using old Archer RS-2031 transistors for the video level drivers.

Is that a single video card ? it looks good.

You know what I am planning to do? To ignore the equalization pulses and the serrations and just create a single vsync pulse together with the hsync pulses. If that doesnt work then I will do a better one

 

Is that a single video card ? it looks good.

You know what I am planning to do? To ignore the equalization pulses and the serrations and just create a single vsync pulse together with the hsync pulses. If that doesnt work then I will do a better one

It actually worked quite well. The main CPU 8080 or Z80 would download the video OS 8080 program to this boards firmware storage on system boot. It had dedicated program, character and graphics overlay memory. I never bothered to generate all of the equalization pulses & serrations and used counters to enforce line video sync timing with lots of glue blanking, sync logic I can't remember anymore. The video output was stable on every composite monitor I used it on.

 

It actually worked quite well. The main CPU 8080 or Z80 would download the video OS 8080 program to this boards firmware storage on system boot. It had dedicated program, character and graphics overlay memory. I never bothered to generate all of the equalization pulses & serrations and used counters to enforce line video sync timing with lots of glue blanking, sync logic I can't remember anymore. The video output was stable on every composite monitor I used it on.

That is a relief to hear! Thank you for that. I am glad to know that those blasted serrations are not needed.

You said you used counters. I am now building on the breadboard a design with just counters. I will just count the clock cycles on each line and each column and output the blanks and syncs depending on the line and column. This sounds like it will work! If it does work I might even add the serrations later on... Do you use facebook?

 

Do you use facebook?

No.