signal shivering on fibre

[neeraj.pola]

hi I am Neeraj from dubai,we are using CSI fibre transmitters and receivers for vga transmission(XGA resolution) for last 3 years ,now we feel shivering on the destination(projector).we send through the signal using a single mode fibre cable.is there is a solution for sorting this issue???

 

,

[Johnparrack]

Firstly, is it an analog Vga connection and not a dvi connection??

 

If so, it sounds as if its the Projectors that has either drifted in terms of Phase or it isn't correctly Pixel mapped, which would give a shimmer to vertical bands of pixels spread across the page.

 

hth

john

[Spyderman]

hi I am Neeraj from dubai,we are using CSI fibre transmitters and receivers for vga transmission(XGA resolution) for last 3 years ,now we feel shivering on the destination(projector).we send through the signal using a single mode fibre cable.is there is a solution for sorting this issue???

 

,

 

Could be computer is on different phase to projector. Make sure they are getting Power from the same Phase/ ring main. Or psu is not in computer properly. Other option could be you have an induction loop to close. It is easy to see if this is a problem, try talking into induction loop and see if lines shimmer intime to your voice. Let me know what the issue is

Thanks and Good luck :)

[Pete McCrea]

It's a Fibre system. Induction Loops could possibly cause interference in the Copper+Analog parts of the system, but aren't physically able to interfere with the Fibre line.

[Spyderman]

It's a Fibre system. Induction Loops could possibly cause interference in the Copper+Analog parts of the system, but aren't physically able to interfere with the Fibre line.

 

Yeah so depends if VGA is close to induction loop!?! My main feeling is the problem is the power.

[David Lee]

Another issue can be if the projectors are truss mounted with lighting on the same truss. We sometimes have to isolate (loads of PVC or rubber matting) the projectors and the signal distro from the truss.

[Solstace]

To the OP:

 

Just to clarify: You say that you *feel* shivering on the projector. Is this fault one feels when touching the case of the projector, or is it something that one sees as a video artefact on the screen? If the former, my money would be on a loose/high-impedance earth line between the projector (or a fibre to electrical signal converter plugged into it) and the mains supply. If the latter... I'll leave that to others more expert than I.

[sleepytom]

Its very unlikely to be a ground loop, as the 2 parts of the system are isolated from each other (fibre acts as an opto-isolator removing any electrical connection between the two parts of the system)

 

Most electricity in Dubai is floating / non earthed anyway (not that that helps anything!) Trying to get anyone to install a proper broadcast grade earthing system out there is hard work!

 

Try and get a scope on the power, I did a job out there where there was huge amounts of HF noise on the power, it turned out to be coming from the UPS system which wasn't earthed properly and was shunting noise that should of gone to ground into our video systems.

 

But as ever start from the source and work along to the projector - check the signal on a monitor where it comes out of the source, before it goes into the fibre, when it comes out of the fibre and when it has gone down whatever VGA distro you have at the far end. If you cannot see the problem on a monitor then it is likely to be an internal projector fault (try an simple autoset to see if the projector can pull it back into range)

[neeraj.pola]

Firstly, is it an analog Vga connection and not a dvi connection??

 

If so, it sounds as if its the Projectors that has either drifted in terms of Phase or it isn't correctly Pixel mapped, which would give a shimmer to vertical bands of pixels spread across the page.

 

hth

john

hi john

 

thanks for ur reply,its basically an analog vga

thanx

neeraj

 

 

A concurrent post has been automatically merged from this point on.

 

Its very unlikely to be a ground loop, as the 2 parts of the system are isolated from each other (fibre acts as an opto-isolator removing any electrical connection between the two parts of the system)

 

Most electricity in Dubai is floating / non earthed anyway (not that that helps anything!) Trying to get anyone to install a proper broadcast grade earthing system out there is hard work!

 

Try and get a scope on the power, I did a job out there where there was huge amounts of HF noise on the power, it turned out to be coming from the UPS system which wasn't earthed properly and was shunting noise that should of gone to ground into our video systems.

 

But as ever start from the source and work along to the projector - check the signal on a monitor where it comes out of the source, before it goes into the fibre, when it comes out of the fibre and when it has gone down whatever VGA distro you have at the far end. If you cannot see the problem on a monitor then it is likely to be an internal projector fault (try an simple autoset to see if the projector can pull it back into range)

 

 

 

thanx Bro..