[time-nuts] Spec An for phase noise measurements

Matt Ettus boyscout at gmail.com
Wed Jan 23 19:43:46 EST 2008

On Jan 23, 2008 4:26 PM, John Miles <jmiles at pop.net> wrote:
> Are you using a noise marker that yields dBc/Hz values?  The FFT window
> function has its own required noise-response correction value, so if you're
> just looking at a marker and doing the log10(RBW) subtraction yourself, that
> could account for the difference.
> Also, if there is a noise marker, check to see if it reads dBc/Hz or dBm/Hz.
> Most of them read dBm/Hz values, which are obviously only equal to
> conventional dBc/Hz values if you're measuring a 0-dBm carrier.

I used the analyzer's phase noise function.  It won't make a plot, but
will do measurements at a few spot offsets.  It's not entirely clear
how it is calculating these, though.


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