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[AMPS] Pi-Net math

To: <amps@contesting.com>
Subject: [AMPS] Pi-Net math
From: measures@vcnet.com (Rich Measures)
Date: Thu, 12 Aug 1999 09:03:20 -0700


>
>?  The problem here is that the Q contribution of C2 is ignored.  The 
>exact method takes into account the Q contribution of C2.  
>
>The "exact" method isn't.
> C2 is not part of the input Z matching section of the pi net
>
True, but C2 stores energy and therefore contributes to overall Q.  

>?  This is 102 pF if you use the Q contribution of C2.    
>
>Input q is no longer 10...it is lower

semi-true.  9.98 in Ian's calculations.  ( C1=102.1pF, L=5.57uH, 
C2=463.9pF, Q=9.98)
>
>?  So, do the experiment yourself and see what you get. 
>
>You get a pi network that is more broadbanded than desired, and has less
>harmonic attenuation than that needed for good design.
>
Not by much.  The main question is whether or not the 7.37 MHz resonance 
changes when RL and Rout are in place?.  


-
-  Rich...
R. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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