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garfield
Joined: 03 Oct 2001
Posts: 39
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 16 Jun 2002 4:24 Video isolator transformer |
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Hi
Anyone know about video isolator transformers design.
Any help be appreciated.
Regards
Garfield
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nandopg
Joined: 26 Apr 2001
Posts: 283
Helped: 5
Location: Over the Rainbow
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22 Jun 2002 1:48 Use a differential Am |
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Dear friend:
You can use a differential amplifier using a matched array of transistors (eg, CA3018). With proper design you can get a CMRR better than 60db. Also you can provide high frequency response compensation, what is highly desirible in video systems.
Another advantage of the Diff Amp over the passive transform is perfect low frequency response, that you can't get from a transform.
Hope to help you,
NandoPG
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garfield
Joined: 03 Oct 2001
Posts: 39
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| 22 Jun 2002 6:33 |
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Nandopg ,
Thanks for you answer!
Really I needd a passive Video Isolator , the only way is design a very
special transformer.
Actually in the market exist very efficient types of this Isolators transformers ( humbuckers ), but the problem is the high cost.
I needd this for eliminate ground loops problems.
all types that I know are passive.
Best regards
Garfield 
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Sebi
Joined: 02 Jan 2002
Posts: 63
Location: Hungary
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| 22 Jun 2002 8:37 |
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Hi,
in my practice this problem always coming from ground-loop since the cameras contains mains-supply with security-ground, and this GND is
common with coax sceen.
Zsolt
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Google
AdSense
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22 Jun 2002 8:37 Ads |
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Theexpert72
Joined: 01 Mar 2002
Posts: 12
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| 25 Jun 2002 21:19 |
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| If common-mode noise is the problem you could also get a big ferrite ring core and wind the coax a couple of times through the ring, this gives quite good suppresion of HF common-mode noise.
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