On Sun, 19 Apr 2009 08:22:53 -0700, Corby Dawson wrote:

Corby,

a real interesting paper, thank you. They seem to think very positive about
this HP type of mixers. That HP/ Agilent is mentioning always their own
model in all their ANs is understandable, but I do not see similar
setups of other institutions or labs with other brands.

Anyway, what they are doing is far more of what I want to. I do not have
access to ultra stable and very low noise oscillators, nor I have small bw.
Spectrum Analyzers and as well no FF-Test devices etc.
I am still setting up my small private lab.

Let me clarify the situation a bit.
The oscillators I work with are mainly 10811 (models A and others),
some reference oscillators of other brands, a PRS10, a LPRO, a FRK-HLN 5MHz,
a Trimble Thunderbolt (with a defective temp. measuring device, try o find out
the impact) and a 1938A, which I have to refurbish,
(is about 4 Hz away from nom. frequency and showing some sudden functional
stops, btw. I need a  v e r y  small 1:4 transformer RFTM-16/SM3, hp 9100-5563,
can somebody help me? I could not find any!).

A lot of work to find out, which oscillator ist the best to serve as reference
and then to classify the others. Not so easy as private and somewhat limited
"test lab".
My TI-counters I use are a 5345A with TI-probes and a 53132A, also a 5334A
and a B model, completed by some other equipment.
(Cs Standards are not on in view :( ).

So, I try to learn and improve the setup by adding a few mixers for the given task,
intending to do things right. Most difficult is to get the needed material here.
(Unfortunately shipment and VAT are a very important counting factor :(  )

Always open I thank you all for the help and hints,
(such dokuments are helpful for a lot of members not yet skilled and
well equipped!)

Arnold

Corby Dawson wrote:

Statements about the low flicker noise of these mixers are sprinkled
throughout the phase noise literature.
Someone must have measured the phase noise of these and other mixers at
some time.

Its relatively easy to measure mixer phase noise:
All one needs is a low noise preamp plus a sound card a 90 degree hybrid
(or a suitable length of coax and a splitter) and a low noise source.

However NIST papers often include a phase noise plot (attached) that
illustrates that high level mixers can have a significantly lower phase
noise than low level mixers (like the HP10514A).
When choosing a mixer for this for phase noise measurement applications
one may actually need to measure the phase noise characteristics of
candidate mixers.

Bruce

On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote:

Wow, a good overview, Bruce!

But remain the questions:
which are these high level mixers, are they readily available?
Are they affordable?
Perhaps not, why are they then not applied more often?

Arnold