Ultra simple video pattern generator circuit needed

[neazoi]

Hi, I need to make an ultra simple video pattern generator (PAL) using a few transistors (discrete only).
Something like a white vertical bar on black background on the TV screen, or any other simple scheme will suffice.

Has anyone got any idea how should I design it, or any existing schematic?

 

[Borber]

Try to make it from 1MHz chrystal and CD4060 combining its outputs.
Simplest thing you can try is astable multivibrator operating on multiple of line frequency. It depends on TV set if it can work without vertical sync and or without horizontal sync.

 

[neazoi]

Try to make it from 1MHz chrystal and CD4060 combining its outputs.
Simplest thing you can try is astable multivibrator operating on multiple of line frequency. It depends on TV set if it can work without vertical sync and or without horizontal sync.

Yes I have seen the 4060 circuit.
I am interested in the astable multivibrator stuff. This circuit is of interest **broken link removed** where somehow you could have it trigered by the blanking pulse. But the blanking pulse has to be made the same as that of the TV?

 

[Borber]

Your circuit is bistabile multivibrator. Blanking pulse can be used for trigger but output frequency will be half of line frequency. You will not have vertical bar but alternating black and white horizontal lines.
It must be astable multivibrator with addition of follower where low impedance losd can be connected.

 

[neazoi]

Your circuit is bistabile multivibrator. Blanking pulse can be used for trigger but output frequency will be half of line frequency. You will not have vertical bar but alternating black and white horizontal lines.
It must be astable multivibrator with addition of follower where low impedance losd can be connected.

Can you give a circuit example?
Thank you

 

[Borber]

https://en.wikipedia.org/wiki/Astable_multivibrator
https://en.wikipedia.org/wiki/Common_collector

Output impedance should be 75ohms and unloaded output voltage 2Vpp.