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


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