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calculate the Q factor of LC bandpass

F

Fred Abse

Jan 1, 1970
0
Oh well. If it is not secret perhaps you could send me a copy of the file
and let me tinker it a bit. I might figure it out.

'Twasn't secret, but it was a while ago. If I can't find it, I'll dream up
a network that 3f will do a .pz analysis on, and let you have it. LTspice
netlists need quite a bit of massage to run in Berkeley 3f, which doesn't
support .param, and other things.

LTspice just barfs at a .pz statement.
 
F

Fred Abse

Jan 1, 1970
0
Oh well. If it is not secret perhaps you could send me a copy of the file
and let me tinker it a bit. I might figure it out.

Can't find the original. Here's a simple file to play with, real poles
only, no zeros.

*pzexample.net
*3 real poles, no zeros
r1 1 2 1k
c1 2 0 1u
r2 2 3 10k
c2 3 0 100n
r3 3 4 100k
c3 4 0 1n
v 1 0 dc 0 ac 1
..pz 1 0 4 0 vol pz
..print pz all
..end


This is what it does in Berkeley 3f:


-- Circuit: *pzexample.net
Date: Sun Mar 17 11:48:01 2013


*pzexample.net
Pole-Zero Analysis Sun Mar 17 11:48:01 2013
--------------------------------------------------------------------------------
Index pole(1) pole(2)
--------------------------------------------------------------------------------
0 -1.011111e+04, 0.000000e+00 -1.363589e+03, 0.000000e+00

*pzexample.net
Pole-Zero Analysis Sun Mar 17 11:48:01 2013
--------------------------------------------------------------------------------
Index pole(3)
--------------------------------------------------------------------------------
0 -7.252998e+02, 0.000000e+00

CPU time since last call: 0.040 seconds.

Total CPU time: 0.040 seconds.

"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
 
J

josephkk

Jan 1, 1970
0
Can't find the original. Here's a simple file to play with, real poles
only, no zeros.

*pzexample.net
*3 real poles, no zeros
r1 1 2 1k
c1 2 0 1u
r2 2 3 10k
c2 3 0 100n
r3 3 4 100k
c3 4 0 1n
v 1 0 dc 0 ac 1
.pz 1 0 4 0 vol pz
.print pz all
.end


This is what it does in Berkeley 3f:


-- Circuit: *pzexample.net
Date: Sun Mar 17 11:48:01 2013


*pzexample.net
Pole-Zero Analysis Sun Mar 17 11:48:012013
--------------------------------------------------------------------------------
Index pole(1) pole(2)
--------------------------------------------------------------------------------
0 -1.011111e+04, 0.000000e+00 -1.363589e+03, 0.000000e+00

*pzexample.net
Pole-Zero Analysis Sun Mar 17 11:48:012013
--------------------------------------------------------------------------------
Index pole(3)
--------------------------------------------------------------------------------
0 -7.252998e+02, 0.000000e+00

CPU time since last call: 0.040 seconds.

Total CPU time: 0.040 seconds.

"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)

Thanks. I have fussed LTSpice for about 2 hour now and cannot get pole
zero analysis at all. Nor do i yet see any easy way to twist its arm. It
may have been only a rumor or someone's moby macro hack.

?-)
 
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