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AM-PM modelling - RF Cafe Forums
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| ben00i
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Post subject: AM-PM modelling
Posted: Wed Mar 21, 2007 7:42 am
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| Lieutenant |
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Joined: Wed Mar 21, 2007
7:08 am
Posts: 4 |
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Hi,
Has anyone ever worked on AM-AM and AM-PM
modelling? If you refer to the following paper by
Saleh, 'Frequency-Independent and Frequency-Dependent
Nonlinear Models of TWT Amplifiers', IEEE TRANSACTIONS
ON COMMUNICATIONS, VOL. COM-29, NO. 11, NOVEMBER
1981, the am-am and am-pm models presented all start
from 0. However, my measurements of both am-am and
am-pm does not start from zero. Do I need to normalize
my result? In that case, how do I normalized my
AM-PM result? It seems weird when the y-axis is
in terms of phase and the x-axis is in terms of
power. Thanks. Love the help u all provide!
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IR |
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Post subject:
Posted: Thu May 17, 2007 4:14 pm
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| Site Admin |
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Joined: Mon Jun 27, 2005
2:02 pm
Posts: 406
Location: Germany
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If I understand your problem correctly:
AM-PM and AM-AM are for providing relative data
and not absolute data. That means that you should
not focus on the absolute values which you get but
on the phase and amplitude differences as a function
of the input power variation. From this you can
draw out useful data about the compression charactersitics
of the PA and be able to characterize the distortion
for designing pre-distortion or other solutions.
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Posted 11/12/2012
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