Bruce Griffiths schrieb:
Support HpW-Works.com wrote:
Bruce,
There's no evidence of a cross power spectrum function in this suite.
One needs to be able to average at least 10,000 cross power spectra
for some
applications.
In the PSD (power density)& PSP (power spectrum) there are cross
power and cross
power complex average implemented (selectable using the spectrum
channel mixer)!
Additional to this you may apply / add averaging of the resulting
spectrum or use
additional peak hold.
Average of 10'000 cross points is a large count and often seen on
1-4k sample size.
Better in my opinion is to use a higher sample size 32k-64k and then
less averaging
is required.
The equivalent phase noise (measured in dBc/Hz) is essentially
independent of the sample size.
So increasing the sample size isnt particularly useful for reducing
the phase noise floor.
The increased frequency resolution achieved by increasing the sample
size is only useful for measuring spurs.
In the direct digital method of measuring phase noise a few
terasamples (a few gigasamples at baseband) need to be processed to
achieve a sufficiently low instrument noise floor.
However with a sound card plus a mixer a somewhat lower number of
samples should suffice since there is no carrier.
Just download the evaluation version with fully feature set.
HpW
Bruce
A HP/Agilent VEE based solution would be much more flexible. There is a
sound card driver available.
I just didn't get deep enough into digital signal processing before the
3562A came...
Adrian
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