Is there anything to split a video signal into vertical, horizontal & blank?

[Videotechie]

Looking for something that splits a video signal into separate vertical, horizontal and blank signals.
Thanks

[jhalphen]

Hi to all,

@Videotechie : it's called a Sync Separator.

Try the National Semiconductor LM1881.
Data sheet :
https://www.ti.com/lit/ds/symlink/lm...oogle.com%252F

Also the Philips TDA2579B, more complex.

See attached files.

Regards
jhalphen
Paris/France

[vol.2]

The LM1881 outputs Vertical Sync and Composite Sync, but it does not output clean Horizontal sync. However, the Composite Sync will be okay for most purposes in a CRT driven signal path.

A device that can just do this for you off the shelf is the Sync Strike. It uses an LM1881, and it outputs over a DE-15 connector, which is the same as a VGA cable output.

If for some reason, you absolutely require clean H sync, you can build a small circuit that gates the vertical portion from the composite sync by using the timing from the vertical sync output. Some PVMs might be picky about this, it depends. Some of them might not take composite as h sync at all, and some of them might show signs of horizontal jitter, or flagging at the top of the screen. It really depends on the monitor.

[Electronic M]

Another option is a composite to VGA adapter that does 640x480 output.... Though some may include a delay in their sync output if they can rescale image size.

[vol.2]

If OP can build their own circuit, the best solution would be to use an LMH1980, as this will do clean H sync, but I'm unaware of any off the shelf solutions that just use this IC. https://www.ti.com/product/LMH1980#tech-docs

[kf4rca]

What polarity does the output sync need to be and what level. Does it need to be
TTL compatible?

[Findm-Keepm]

Many OSD chips (inserters) separate the sync and blanking signals.

Maxim made a few, for the security industry, which entered Time Code iinfo into the video chain and needed the sync signals to correspond. EDIT: Heres the MAX7456 eval board, but in CHina....
https://www.ebay.com/itm/135132712344

The old eval board(s) are what you want, as the chips, for the most part are obsolete.

I had several, but no more. Great thing about being an EE student with nice professors - they'd sign any Maxim/NSC/TI/Freescale student form. Free chips! (I mostly went for the National audio power amps and the Maxim "DIP of the month" stuff - MAX038, MAX7XX stuff, the pattern generators, the op amps, some Elantec stuff, you name it - 2 sample chips, delivered to your door, free. TI still does the free samples for students, but you almost have to beg them, with a design concept signed by a professor.

[Findm-Keepm]

https://www.ebay.com/itm/252880419063

Specs: https://archive.org/details/vasulka1...e/n31/mode/1up

[Videotechie]

Do appreciate all the input.
Some people on web same or similar but not responding if making any units for other people.

Thank You

[kf4rca]

How about this?

It used to be that many semiconductor manufacturers had local offices in the major markets and you could stop by there and the sales manager could order up free samples for you.

[kf4rca]

A sync separator schematic that uses only three transistors. I used this circuit in a character generator I built many years ago. This character generator uses dip switches to select the characters. A maximum of 8 characters can be displayed.
It was not an easy project. The timing circuits (from the TV typewriter article) takes NINE chips. I used the General Instrument character generator chip (RO3-2513) as it requires only +5 instead of the Signetics chip which also requires +12 and -12. The character video is simply mixed with the incoming video rather than being keyed.
The advantage of a discrete sync separator is you can adjust component values to your application and you probably already have the parts on hand.

[Videotechie]

Where in that circuit for separation is there a connection for z axis .?

Thanks

[Videotechie]

Thanks for info on lm1881 very useful. Did anyone use this to display a video signal on an o-scope??

[jhalphen]

Hi to all,
Hi Videotechie,

What you call "Z axis" is actually the analogue video modulation applied to the oscilloscope or X/Y display's Cathode or Grid to produce a picture.
In a standard 1 Volt peak-to-peak video signal, the brightness intensity (Black to White) is the 0.7V (700 mV) analogue signal contained between the blanking level (0.3V) and peak White (1V). The complete signal with Sync is 1V Peak to Peak.

Labguys World web site shows two projects he built to use a X/Y display as a 525 line/60 Hz TV monitor (standard System M/NTSC scan rates). Both circuits use the LM1881 as a Sync separator and give good insight into what is necessary to achieve the desired goal.
Schematics, photos & extensive explanations in both projects.

1st project :
http://www.labguysworld.com/Project_Tiny_TV.htm

2nd project :
http://www.labguysworld.com/Project_Tiny_TV_2.htm

Best Regards
jhalphen
Paris/France

[kf4rca]

The CRT gets the full video signal, including H & V sync and color burst. There is a special type of monitor called a pulse-cross monitor that allows you to see the sync (and color burst) present in the signal. It's used mainly in control rooms and quadruplex vtr's.
On a color monitor the burst looks like a green stripe right after the H sync.
Some time ago somebody had a circuit that you could add to a regular monitor and it would delay the sync pulses so you could see them.