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coax amplitude ripple issues - RF Cafe Forums
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Henryk
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Post subject: coax amplitude ripple issues
Posted: Mon May 29, 2006 3:11 am
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Joined: Mon May 29, 2006
3:07 am Posts: 2 |
I'm having some issues testing our system- I can't
shake the amplitude ripple I'm reading from the
coax cables I'm using. I've tried changing cables,
using different lengths, making sure connections
are tight, having isolation in the path, and nothing
is working.
Any thoughts? I'm testing in
a high heat/humidity region, so maybe that's the
issue . . .
Thanks so much.
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VSWR |
Post subject:
Posted: Thu Jun 01, 2006 11:05 am
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Joined: Sun Jan 11, 2004
4:44 pm Posts: 18 |
Are you sure that the cables & connectors are
rated for the frequencies that you're operating
at? If you're transmitting anything with a square
edge, then you;d better make sure that the cable
is rated at least 5x your highest fundamental or
the harmonics that make up the edges will be reflected
and possibly be causing your amplitude ripple.
Otherwise, maybe the impedance of your source
and/or load are not close enough to the cable/connector
impedance and you are seeing VSWR (that's my name!)
mismatch induced ripple. If your source/load is
even 10 ohms off of your transmittion path impedance
the amplitude ripple can be noticealbe of long distances.
You didn't mention how long the cable run is
or your signal frequency & modulation type,
so all I can do is make these guesses. Hope they
help.
--- VSWR ---
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Henryk |
Post subject:
Posted: Thu Jun 01, 2006 9:13 pm
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Joined: Mon May 29, 2006
3:07 am Posts: 2 |
I'm in the 10-13 GHz region. I'm using the appropriate
isolators, and my cable runs are only around 12ft.
However, in talking with a senior RF tester, he
says that my adapters may be causing the issues-
I'm using a fair number of adapters to connect my
SMA isolators to my N-type coax. Minimizing them
may be the key. Any thoughts?
Thanks for
your input.
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Posted 11/12/2012
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