brooke at pacific.net
Tue Sep 30 14:20:32 CDT 2003
I had a look at you web page for LF and have some comments.
LF Impedance "AMRAD Presentation on LF Impedance Measurement"
The method in the paper is very similar to the one in HP patents
5,345,182 and 5,463,323. I think these were for the 4191A Impedance
Analyzer. A classical bridge has the measuring instrument connected with
both ends above ground and that's not so good for RF measurements, so a
balun can be used. . . .
I have been making some measurements on how the characteristic impedance
of a transmission line varies with frequency when the frequency is below
the line corner frequency. To make these measurements in the 10 Hz to
500 kHz range I have been using the HP/Agilent 4395A Network Analyzer
and the Z Transformation method. See:
The Z transformation method measures the DUT connected in series between
the center conductors of a normal network analyzer test setup , like an
S21 measurement. Then the analyzer does the math to convert the result
into impedance and can be displayed as Lin Mag, Log Mag, phase, real or
imaginary. The beauty of this method is that it can be used over the
full 10 Hz to 500 MHz range of the 4395A. Note that the 43961A Impedance
test kit only works above 100 kHz. The 43961A uses the technology of the
above patents. It may be possible to home brew a version of the 43961A
that would work lower in frequency.
The Z Transformation method is what's used in the HP/Agilent E5100
series High Speed Network Analyzers that are specifically designed for
PS the spiral graphic in this paper takes a very long time to download.
A plain white background pdf version would make net viewing a lot less
Larry Kaysers,, PIC Program .ASM file
What does this program do?
Low Pass Filter?
The reason I Was on this page was to find details of a low pass filter
to use with your active LF antenna which I now have.
Have their been any updates on the power supply to reduce the line
conducted noise that I found with the original design?
Brooke Clarke, N6GCE
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