[time-nuts] Phase noise measurements - getting started.

Jeffrey Pawlan jpawlan at pawlan.com
Sun Apr 24 12:00:10 EDT 2005

Regardless of whether you build your own phase noise measurement setup from
parts or whether you purchase an already complete system made by Agilent or
others, you will still face the reality that there are only three ways to
measure phase noise and you mentioned them in your previous email:

1.  Start with a frequency source that is more than 10dB better phase noise than
the one you want to measure. This is difficult when measuring a HP10811

2.  Use two or three identical oscillators.  This works if all are really the
same but does not work if one of them is significantly different.

3.  For measuring much poorer phase noise sources and for measuring further
from the carrier than we are interested in, one uses a delay line discriminator.

Having access to a calibrated commercial measurement system will not assist you
at all unless you can find other oscillators that meet the criterion. Those
systems do not contain the comparison signal sources unless you are measuring
something with phase noise much poorer than the 10811. Then they are simply
using a moderately low noise synthesised signal generator as one of the
comparison sources.


Jeffrey Pawlan, WA6KBL

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