Rick,
thank you again for having pointed me to the AMC123 that were just
available when you mentioned them.
Part of the magic is the 10 dB gain and typical +23 dBm output.
So, you don't saturate it with a 10811, which would be bad in terms of
phase noise, and, on the other hand, if you overdrive it accidentally,
there is no risk to damage the +23 dBm mixer (phase detector) in the
11848A test set.
There are some other interesting Anzac models featuring the lossless
feedback design, but this one fits best.
I was lucky to find some Q-Bit anps (QBH-137 and 138) that are based on
an almost identical patent but, with 12 to 15 dB, have more gain and
maybe slightly higher PN.
Anzac patent: 3,624,536 which is the original David E. Norton patent
from 1971.
Q-Bit patent: 4,042,667 from 1977
http://www.freepatentsonline.com/4042887.pdf
To comment on the Mini Circuits amp, for my needs it has way too much
gain and +5 dBm 1 dB compression makes it completely useless for PN
measurement purposes.
Adrian
Rick Karlquist schrieb:
It is good that you asked this FAQ. Basically, what is magic
about the AMC-123 is that it has certifiably low phase noise,
guaranteed by design and characterization, although not specified
by Anzac. The other 99.9% of amplifiers that seem plausible, like
this one, do not have the sophisticated negative feedback scheme
of the AMC-123, and likely do NOT have good enough phase noise.
In any event, we have zero information about the phase noise of
this Mini-Circuits amplifier. Having a low noise figure is necessary
but not sufficient to have good phase noise.
Of course you could always get lucky. But then you have to also
build an amplifier phase noise measurement system, which generally
entails a line stretcher.
Again, thank you for asking this question. It comes up often.
Would anyone else like to suggest a known good low phase noise
buffer amplifier? Maybe something from a Fred Walls paper?
Rick Karlquist N6RK
Mark J. Blair wrote:
On Aug 20, 2010, at 11:17 AM, Rick Karlquist wrote:
On the 10811 production line, they would use Anzac AMC-123 amplifiers
How does this amplifier look for this application?
http://minicircuits.com/pdfs/ZFL-500LN.pdf
If I understand the specifications properly, the noise figure is better
and it has higher reverse isolation and higher gain, but a lower output
intercept point.
--
Mark J. Blair, NF6X<n...@nf6x.net>
Web page: http://www.nf6x.net/
GnuPG public key available from my web page.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
