[time-nuts] HP phase-noise measurement seminar coursebook

[Brooke Clarke]

Hi John:

Some recollections and comments after reading the seminar paper.

When making automated mixer spur measurements using the HP 8566 spectrum 
analyzer and HP 8350B sweep generators, both under HP-IB control the phase 
noise of the 8350B was so bad you could not make a measurement.  With the RBW 
set very side you see just a line but as the RBW is narrowed down you start to 
see the filter shape and at narrower settings you see gibberish because the 
signal has FM noise.  Switching to synthesized sources allowed the RBW to be 
narrow enough to get the noise floor down where it needed to be to see the 
spurs.  That eye opener was my introduction to phase noise.

In the Phase Noise paper you'll notice that for a number of measurements the 
11729B is needed in addition to the 3047 and that when this is done often the 
automatic features of the 3047 are not used.  I.e. you don't need the 3047 for 
those measurements.  I ended up rolling my own automated phase noise systems 
based on the information in the 11729B manual that had an 11729B (usually with 
all the optional bands installed just to avoid chasing down the one that was 
needed) and one of the good phase noise HP signal generators along with the 
Rocky Mountain Basic computer.  All this would fit a 4 foot tall rack on 
wheels.  Made a number of them.

When talking about the straight spectrum analyzer method of measuring phase 
noise they discount the non synthesized analog spectrum analyzers and focus on 
the synthesized analog SAs.  But what's not mentioned are the synthesized 
digital spectrum analyzers like the HP 4395 and 4396.  These have true 1 Hz RBW 
settings and also have true RMS signal detection that avoids the corrections 
that are needed when an analog SA is used BUT they are not mentioned in the 
paper.  I think this is because they are made in the Kobe, Japan division of HP 
and are not U.S. made products.  Kobe is also where the LCR meters and 
impedance analyzers come from.

I've downloaded your Phase Noise software but have not yet tried it out on my 
4395A.  http://www.prc68.com/I/4395A.shtml
I think all that's needed is to enter 0 dB into the Noise Response window 
instead of the +2.5 db for a peak detector and -0.5 db for RBW correction 
needed for analog SAs.

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam


John Miles wrote:
> ); SAEximRunCond expanded to false
> Errors-To: time-nuts-bounces+brooke=pacific.net at febo.com RETRY
> 
> This seminar was given June 14, 1985 at Red Bank, NJ.  Its handout covered
> pretty much every bit of information and lore HP had to impart on
> phase-noise measurement.  Anyone interested in PN measurement with 80s-era
> hardware (8566/8568/3585A, 11729B/C, 3047A, etc.) may want to download a
> copy of the course notes that I just scanned.
> 
> http://www.ke5fx.com/HP_PN_seminar.pdf (124 pages, 7 MB)
> 
> -- john, KE5FX
> 
> 
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