Help with Vector Voltmeter measurements
 

I recently purchased an older model HP8753 Vector network analyzer. It came
with the reflection test set and calibration standards.

I have looked for some time on the net and cannot find any documents that
describe how to make practical measurements.

Initially I want to characterise some passive components (caps etc) and I
also want to be able to measure the unput impedance of an active device.

Can someone please point me in the right direction or maybe explain how I
set up a test. I have seen responses in books showing the impedance of a
capacitor and the self resonant response but when I connect a Cap to the
test port on the reflection test set I can see the correct capacitance curve
on the Smith chart display but when I switch to mag, the line is flat acorss
the band. I cannot tell from the Smith Chart where it is self responant.

Thanks in advance for any help

Regards

David

Help with Vector Voltmeter measurements
 

Hi David,

You wrote:

Initially I want to characterise some passive components (caps etc) and I
also want to be able to measure the unput impedance of an active device.

When you measure a passive component, you may want to measure the
capacitor shunted on the transmission line. Consider, in your mind,
what will happen at DC and at infinite frequency when these two
different signals see this network. At DC, the capactitor is an open,
so we should have full power transfer, and at infinite freq, the
"ideal" capacitor is a short, so we should have zero transfer of
power. Obviously, this is not the case of a real capacitor. It acts
like a capacitor up until it hits it's self resonant frequency (SRF)
then it starts becoming more inductive as you increase in frequency.
You should see this on your log plot when you measure S21 insertion
loss with the capacitor shunted on a transmission line between ports 1
and 2.

FH