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RF design - simple question - RF Cafe Forums
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| matrixrf
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Post subject: RF design - simple question
Posted: Wed Mar 07, 2007 3:50 pm
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Joined: Wed Mar 07, 2007
3:42 pm
Posts: 1 |
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What effect does return loss have on Transmit Power?
Is it a one to one correlation?
eg. Tx power
is 30 dB
RL = -12 dB
What is actually
transmitted?
Thanks
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Kirt Blattenberger
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Post subject:
Posted: Wed Mar 07, 2007 5:53 pm
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| Site Admin |
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Joined: Sun Aug 03, 2003
2:02 pm
Posts: 676
Location: Erie, PA
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Greetings matrixrf: Return loss is the relative
power of the reflected part of the signal, and the
remaining power gets through to the antenna. For
your case, the reflected signal is 30 dBm - 12 dB
= 18 dBm. To get the final transmitted power number,
you need to convert those powers to watts, subtract,
then convert back to a dBm value. 30 dBm
= 1000 mW (incident power) 18 dBm = 63.1 mW (reflected
power) (1000 - 63.1) mW = 936.9 mW (transmitted
power) 936.9 mW = 29.7 dBm For dBm <-->
mW conversion see here:
http://www.rfcafe.com/references/electrical/mw2dbm.htm
_________________ - Kirt Blattenberger
RF Cafe Progenitor & Webmaster
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Posted 11/12/2012
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