[time-nuts] Keysight N5511A - phase noise measurements down to theoretical-177 dBm/Hz

[jimlux]

On 8/22/19 5:55 AM, Anton Moehammad via time-nuts wrote:
> The cost of this N5511A started from 135K USD is there anything I can buy or build for less than 1K USD for phase noise measurement ?
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Have you come to the right place!
There's tons of things you can do to measure phase noise for less than $1k.

I do have to warn you in advance.. this is sort of like car racing, "how 
fast can you afford to go". (Clearly, you can get to $150k, which is a 
whole lot less than a fast race car)

What kind of phase noise levels are you looking to measure, at what 
center frequencies and how far out from the carrier, and I'm sure the 
list will respond with help...

Most of the schemes rely on mixing your input signal with another (very 
quiet) signal, and then measuring the noise in that downconverted IF. 
The phase noise measurement feature of a spectrum analyzer does this, 
down to the noise floor of the analyzer.  These days, running the 
downconverted signal to an ADC, sampling it, and post processing is 
popular (that's probably what the spectrum analyzer is doing).

As always, the details are important.

Some searching of the archives will turn up ideas, but you'll need some 
key background knowledge to pick the right search terms. And some of 
that depends on whether you're interested in measuring phase noise (say, 
from 1-10 Hz and out) or Allan Deviation (in all of its forms)...

Let us know what you're trying to do..