[time-nuts] Re: Working on a low-phase-noise frequency multiplier

[Bill Ezell]

Ok, decided I'll try the MK-3. If it's satisfactory (and I'm sure it 
will be, this is all mostly just for fun), I might do up a little box 
with a gain block and maybe a bandpass filter in it.

Although figuring out a regenerative multiplier would be a lot of fun. 
That seems to have been very popular back in the past. The HP5061 used 
regenerative dividers, the Sulzer 2.5A and 5A xtal stds did also. Sulzer 
in particular has some fascinating stuff for doing frequency division 
for its outputs. Complex. Regenerative dividers, regenerative 
multipliers, mixers, etc. There must have been a reason, right? Example, 
the S 5A gets 1Mhz from its primary 5Mhz by using a regenerative 4Mhz LO 
and mixer. No external LO source. Cute because of course the derived 
1Mhz doesn't depend upon anything other than the primary freq. The 
spectral purity is pretty good.

BTW, my test setup is an HP 53310A using a Trimble GPS std of my own 
design as its ref input. The 53310A is a hugely unappreciated bit of 
kit, capable of measuring to theoretically e-14 with long averaging. 
And, calibration is trivial. Push some buttons. Unlike the awful analog 
fiddling needed for a 5370. And yes, I have several of those I no longer 
use for anything.

Bill

On 8/27/2023 2:18 PM, wkb at xs4all.nl wrote:
>
> Hi Bob, Bill,
>
> Just to satisfy my, and maybe part of your, curiosity I ran some 
> experiments. Coincidence has it that I own a Minicircuits MK-3 
> doubler. It was part of the original Efratom MRK setup, it sat between 
> the FRK Rb and the MGPS module.
>
> Anyway, on the SA it looks like in the attached screenshots.
>
> Legenda:
>
> - Plain-Efra-FRK is the spectrum obtained directly from the FRK-HLN
>
> - The two Efra-MCL-MK-3-doubler-* are as the name implies the spectra 
> from the MCL MK-3
>
> - The Efra-builtin-doubler-V1.BMP is based on the design at 
> http://www.timeok.it/wp-content/uploads/2015/08/high-performance-frequency-doublerv1-31.pdf 
> <http://www.timeok.it/wp-content/uploads/2015/08/high-performance-frequency-doublerv1-31.pdf>Â  
> V1 refers to the first prototype version of the PCB designed by Dave 
> PA5DOF.
>    ( 'builtin' references the fact that it is  builtin my Efratom 
> rack). It might be worth noting that that the spectrum was obtained 
> from one of the Efratom MBF distribution amp outputs, so not directly 
> from the doubler.
>
> Â Â The spectrum It is not as clean as shown on the referenced web page.
>
> Dave's and my joint rabbit hole led to the design of a V2 PCB to 
> correct some minor layout goofups in V1. Which, as Murphy dictates, 
> has fresh anomalies with the 5 MHz input signal 'punching through'. 
> Reason is  as of yet under investigation. This is screenshot 
> "v2-doubler-nieuwe-trafo-en-L4-C.bmp. "No Good" ☹
>
> I do not own something which can measure phase noise (i.e. the HP 
> 8595E SA really does not qualify) so I cannot tell you how things 
> compare on the PN front.
>
> Best,
>
> Wilko
>
> <mailto:time-nuts-leave at lists.febo.com>

-- 
Bill Ezell
I happen to know that this is the Lupin Express.