[time-nuts] Re: DIY Low offset Phase Noise Analyzer (Erik Kaashoek)

[Bob kb8tq]

HI

We’re not building a synthesizer here. We are putting together
a simple piece of test gear. The purpose of the test gear is to 
measure phase noise down into the -170 dbc / Hz range …..

Bob

> On Jul 12, 2022, at 4:05 PM, Mike Monett via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> To Bob kb8tq:
> 
> Unfortunately, most of your post made very little sense. D-flops are noisy,
> and the higher you go in frequency, the noisier they are. This is clear
> from the schematic. Here is the schematic for a MC1670 D-flop: MC1670SC.PDF.
> 
> Most of the noise is generated in the input SR latch. When the clock signal
> arrives, the input latch state is transferred to the output SR latch.
> Obviously, the sheer number of transistors involved is going to generate
> noise.
> 
> Unfortunately, the D-flop is needed in every known synthesizer. Keeping
> this noise out of the signal is the goal of every designer. Stanford
> Research Systems is one company that has mastered the art. See
> 
> https://www.thinksrs.com/products/siggen.html
> 
> But you need to know how much noise is involved. That is where my new
> method can help. I am busy collecting parts - the HMC984LP4E's will arrive
> tomorrow, and I am looking for a pair of low noise VCXO's.
> 
> I will have to regenerate test equipment that I haven't used in 5 decades
> to measure deadband, loop bandwidth, damping, crosstalk, jitter response,
> etc. I will also get a DBM to compare the results.
> 
> I will also need ripple filters for the electronics. I have described this
> before in 2N3906G.PNG
> 
> All this will take time - maybe months. But I have intended on making my
> own phase noise analyzer for a long time, and this will be an excellent way
> to get started.
> 
> Along the way, there are plenty of other projects to attend to: a 4GHz to
> 8GHz low noise signal generator using YIG oscillators, a GPSDO to supply an
> accurate 10MHz reference, a new method of eliminating the sampling jitter
> in the 1PPS signal from the GPDSO, a low noise VCXO to supply a 10MHz
> reference from the 1PPS signal, an ultra stable signal generator to allow
> sampling of signals up to 150GHz, and so on.
> 
> As there is little else to talk about, I will go silent while I am working
> on these projects.
> 
> Bye
> 
> Mike
> <MC1670SC.PDF><2N3906G.PNG>_______________________________________________
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