Input and output impedance standards for video signals?

[ELS122]

Is the input impedance the standard for all analog and digital signals, 75 ohms?
what about the output impedance, is there a standard output impedance for video?

[boB]

AFAIK, yes.  75 Ohms  for input and output on video.

[Benta]

Yep, 75 ohms for output, input and cable. Professional video uses 75-ohm BNC connectors for RGB/Sync. Dunno what you mean by digital video in this context?

[ELS122]

Yep, 75 ohms for output, input and cable. Professional video uses 75-ohm BNC connectors for RGB/Sync. Dunno what you mean by digital video in this context?

I mean video standards such as HDMI as digital.

so if an input asked for 1V ptp, I'd want a 2V ptp signal trough a 75 ohm resistor (or less depending on the buffer impedance I'd use), to result in a 1V signal after it was loaded by the input of a monitor/tv

[ELS122]

Would one driver circuit be better than the other in the schematic I attached?
would the bottom circuit have problems with the base of the transistor picking up noise from other components nearby?

actually I realized that the top circuit wouldnt work too good since it would have an output impedance of actually 400 ohms from the large impedance supplying the base

[Terry Bites]

A standard is a standard . 75R is used to get greater bandwith that a 50R will give. A 75R cable is lossier but has lower group delay. 50R is narrow band. An FM radio broadcast may have a bandwith of 200kHz. SD video will need 4.35MHz

Digital video uses 110R, often sent over 75R using a matching transformer. It's worth learning how to tell a 50R BNC from a 75R BNC, a subtle difference.

Pro analog audio uses 600R as do copper  telephone lines.

You dont need an emitter resistor to gnd if you DC couple. Send a current not a voltage. Just drive the line from the emitter via a 75R. .Avoid caps if you can. Sag and such.  Video line drivers are very low cost items, they abound in consumer video kit. EG THS7316DRG4

[Benta]

I mean video standards such as HDMI as digital.

So why do you ask about analog video? Wasting our time for fun?

[ELS122]

I mean video standards such as HDMI as digital.

So why do you ask about analog video? Wasting our time for fun?

no, I asked for video signal standards, I was interested in both, accidentally said 'analog' in the post, since I didn't find any datasheet or specification sheet online for neither.

[NiHaoMike]

Almost every digital video standard uses differential pairs with about 100 ohms impedance, the biggest exception being SDI which was meant to run digital video over existing analog video cables.

[Terry Bites]

www.maximintegrated.com/jp/design/technical-documents/tutorials/1/1184.html

There is always the ITU, founded by Napoleon III.  www.itu.int  Still owned an operated by petty dictators I imagine. Actually they're decrepit bond villains but I'm splitting hairs.
ISO/IEC JTC 1/SC 29

You used to have have to include a picture of a young woman looking back over her shoulder to demonstate video standards.
Standards have improved and thankfully this is no longer a requirement.

[Datman]

With 39 or 180 ohms to gnd, output impedance will surely be lower than 39+39 or 180+68 ohms!