• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Analogue Video over a laser beam

kimbear

Member
Is there any way to send NTSC COMPOSITE from a video camera NTSC Analogue Video over a laser beam.
I only need a distance of about 12 inches. The beam would be under a cover, so it wouldnt be killed by ambient light.
Is there any way to do this inexpensively.
I was going to remove the laser, and pick-up from a DVD Player, but then I thought that the lack of a disk, and its regional data would stop it from operating.
Whatcha all think?
Again, thanks in advance for any help
 
Last edited:

kimbear

Member
Im trying to send a video signal over a short distance thats all, I would prefer not to mention why. Im sorry about that
So what are your thoughts nigel??
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Im trying to send a video signal over a short distance thats all, I would prefer not to mention why. Im sorry about that
So what are your thoughts nigel??
My thoughts are you can't answer vague questions - it can be done, but there's no point considering it without full details.

Edit: You might try looking at video to fibre converters?, as it's such short range.
 

AnalogKid

Well-Known Member
Most Helpful Member
What is the video source? Monochrome, color, NTSC 1 Vp-p, PAL, composit, R-G-B, Y-R-B, SVGA, etc. - ?

ak
 

kimbear

Member
It would be composite video from a camera. NTSC....but to be honest, I could input almost any signal, if it would make it easier to do.
 

AnalogKid

Well-Known Member
Most Helpful Member
Performance parameters: differential gain, differential phase - ?

Both amplitude modulating a laser diode and receiving the laser energy with a photodiode or phototransistor are *very* non-linear processes. Also, we're talking about a 10 MHz signal bandwidth. (4.2 MHz plus some margin to minimize phase distortions). What is your skill set for this type of circuit?

ak
 

schmitt trigger

Well-Known Member
I would take the baseband video and modulate it with any of the very common modulator ICs.
These ICs were extremely common, all the VCRs, set-top cable boxes and video games had one.

Then demodulate it again with any of the ubiquitous demod ICs for TVs and recover the baseband signal.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I would take the baseband video and modulate it with any of the very common modulator ICs.
These ICs were extremely common, all the VCRs, set-top cable boxes and video games had one.

Then demodulate it again with any of the ubiquitous demod ICs for TVs and recover the baseband signal.
I'm completely baffled by this post?.

If you mean the RF modulator in a VCR etc, then these didn't usually use IC's, as there's no point, and modulating an RF carrier isn't what he wants to do.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
is there not a laser, and a receiver to bounce off the surface of a DVD??????? or am I mistaken????
It's all in one unit, intended to work over a few mm, and entirely digital.

Presumably you've also considered the safety implications?, it's a class I laser device, and only for use in a sealed unit where it can't be visible.
 

unclejed613

Well-Known Member
Most Helpful Member
it's a class I laser device, and only for use in a sealed unit where it can't be visible.
and even reflections off of other objects can be dangerous to your retina...

you could use LEDs instead.... you would need to look at spec sheets and try to find LEDs with very low junction capacitances allowing wide signal bandwidth... for instance a Vishay through-hole LED has a junction capacitance of 50pf, which has a reactance of over 300 ohms, and so would be ok for a bandwidth of 10Mhz. to improve signal strength, you could probably drive a series string of several LEDs in a group
 

kimbear

Member
and even reflections off of other objects can be dangerous to your retina...

you could use LEDs instead.... you would need to look at spec sheets and try to find LEDs with very low junction capacitances allowing wide signal bandwidth... for instance a Vishay through-hole LED has a junction capacitance of 50pf, which has a reactance of over 300 ohms, and so would be ok for a bandwidth of 10Mhz. to improve signal strength, you could probably drive a series string of several LEDs in a group
I have no problem with it being a super bright LED instead of a laser.
 

Latest threads

EE World Online Articles

Loading
Top