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Discussion Starter · #1 ·
I tried searching the forum for a more exact, and preferrably a picture, of this.


Does anyone know off hand a topic thread that covers this?


Following Mr.Wigggles suggestion I made a 30' Cat5 breakout component cable but I am seeing some wavy transparant lines slowly travelling northeastward throughout the pictures. The lines are only faintly noticeable but is still rather annoying compared to my original 30' premium VGA cable that did not exhibit this. http://www.avsforum.com/ubb/frown.gif


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Editor of the AVS Skyworth FAQ and Official Panasonic RP91 Firmware Upgrade Request from OWNERS pages.
 

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I think ringing is that weird bright shadow you see on the edges of objects that results from the use of sharpness circuits or Edge Enhancement (EE) on DVD's. Please someone correct me if this is wrong. Shadows come from cables that have the incorrect impedance, and the transparent moving diagonal bars you describe sound like EMI/RFI interference. If the 30' VGAcable was working, why did you change?
 

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Ringing id not Signal leaking in... that would be interference.


Ringing is caused by an impedance mismatch in a video system. What happens is in a perfect system (all matched imedances. in our case 75 ohm) is that all the infomation is 100% transferred from point A to point B (or also C D and E) and you have a clean image. If the impedance is not matched (too much variation in connectors, termination, or cabling) then you do not get a 100% transfer of energy. SOme energy does not make it to the destination and is reflected backwards in a system. this energy then starts to bounce around and makes it eventually to the display device but after the original signal. it shows up slightly to the right of the original. or sometimes it appears a couple of times.

http://www.avsforum.com/ubb/image_up...ables-4ppt.jpg


Sometimes this is an effect that is actually present in the design of the projector. we call that a feature.


This ghosting/Ringing/Impedance mismatch can come from either equipment somewhere in your system, or cables. A note though, i believe those who tried this did it with SHIELDED Cat 5 cable. YOu might want to confirm that you have shielded cable. And check your termination. A poor solder can cause a world of difficulties.
 

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William,

Thanks for the link on EE. It is very helpful.


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Todd

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Discussion Starter · #6 ·
Quote:
Originally posted by Dizzman:
A note though, i believe those who tried this did it with SHIELDED Cat 5 cable. YOu might want to confirm that you have shielded cable. And check your termination. A poor solder can cause a world of difficulties.
Thank Dizzman.


I am using a SHIELDED Cat. 5. As far as termination I'm not sure what else is there to check. I will redo the soldering to see if this helps.


I tend to think it is interference also being that the conduit has other wires (speaker cables, optical cables, phone wires) but I thought that's what the SHIELDING is for... http://www.avsforum.com/ubb/frown.gif


By the way I made a 12 inch (1 foot) version of the same breakout cable with the same materials and that seems to work perfectly. http://www.avsforum.com/ubb/smile.gif


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Editor of the AVS Skyworth FAQ and Official Panasonic RP91 Firmware Upgrade Request from OWNERS pages.
 

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