[time-nuts] Minicircuits SYPD-1

Wed Dec 19 18:15:59 UTC 2018

Hi

If indeed the only purpose here is to do a phase lock, then this is being *way* over complicated. 
There is no need for anything past a simple mixer followed by the loop amplifier. There are always
going to be minor bits to keep RF out of here or there, but they very much depend on exactly 
how you are doing things. 

The “why” is pretty simple - any TimeNut category source is not going very far when in phase lock. 
They will be quiet and there is no modulation to worry about. If you are out past 90 degrees, you 
aren’t locked ….

====

The “typical” way to play with the baseband I/Q stuff is to digitize both and then do the math in the CPU …
Yes, that makes a lot of assumptions about the end goal. 

Bob

> On Dec 19, 2018, at 1:04 PM, Jerry Hancock <jerry at hanler.com> wrote:
> 
> Thanks to all that replied, lots of good info which will take me months to sort through, especially the link to Jürg Kögel looks helpful as well as a note from Bert.
> 
> Attila, Yes, more phase noise than long term though this is really an exercise to get a better understanding of oscillators and measurement techniques.
> 
> The 2n2222 mixer sounds like another H-mode, I’ll have to look at it.  It probably uses self-wound, micro-sized bobbins which will be a challenge for me :-].
> 
> Bob, I think you were the person who pointed me to the loose PLL a while back.  The circuit I am building used a gain of 300ish (30k/100) and I expect that to really clip when unlocked.  I have a 10-turn variable in the circuit to bring it close initially. 
> 
> Another question or if you can point me to the method, if you are using quadrature signals, is the measurement then the geometric sum? Or do you mix them back together?  I am using a 3457a on the PD after an amp right now and I would think you would need either another meter, which I have, or a scanner, again I have both.  
> 
> My N2PK VNA uses two 24bit, low noise ADCs (LTC2410) for the same purpose more or less. It has effectively two DC receivers with two DDS. I can throw away the DDS and mixers and just read the DC voltage.  I have a second N2PK board I never finished as I planned to use another master oscillator on it with lower PN, but I needed a couple of parts and my tremor made SMD soldering difficult.  This was one of the drivers for my interest in phase noise. Now that I think about it, I can repurpose the second board, bypassing the MC1496 mixers. They are filtered to be close to DC within a few hz and has -135dB noise floor.  I can even change the input filter to use the 220 ohm/.0046uf R/C recommended.
> 
> I wish there was a way to use or modify one of my 8568B Spectrum analyzers to do this.
> 
> Regards,
> 
> Jerry
> 
> 
>> On Dec 19, 2018, at 7:57 AM, Attila Kinali <attila at kinali.ch> wrote:
>> 
>> Hoi Jerry,
>> 
>> On Tue, 18 Dec 2018 23:18:42 -0800
>> jerry <jerry at hanler.com> wrote:
>> 
>>> I'm playing around with various methods of collecting data for
>>> oscillator testing and would like to try the loose PLL which
>>> requires a phase detector (PD).  
>> 
>> I guess you are looking more into phase noise than stability?
>> 
>>> I'm testing an AD8302 but that has a flat spot around 176 to 180 degrees.
>> 
>> All phase detectors exhibit non-linearity in some form or other.
>> If you get all the way to +/-176° with good linearity, then be
>> happy. If you need more than that, then you have to either use
>> two phase detectors that are driven with a reference that is 90°
>> apart, or you have to digitize the signal and do the same in digital.
>> 
>>> One of the papers I read recommended the subject PD but it is out of
>>> stock everywhere, including the subs. One Minicircuits PD is in stock but
>>> pricey.  I can try a double balanced mixer like the SBL or TUF series (which
>>> I have on hand) but I thought maybe someone on the list has the subject PD
>>> they dont need. If so, please send me a note.
>> 
>> There is a decent alternative: Use two transformers and 4 2N2222 to
>> do your own mixer. The quality of it, according to NIST[1] is pretty
>> good. I assume that any other NPN transistor of similar make-up will
>> also do and lead to same/similar performance.
>> 
>> You might also want to have a look at Enrico's Mixer Tutorial[2]
>> 
>>> I'm slowly gathering parts for Riley's small Dual Mixer Time Difference
>>> test kit but it will take some time which I'm unfortunately running out
>>> of due to mild Parkinsons getting in the way of SMD soldering. I've used
>>> my HP 5371a in the past but it sounds like a jet engine.  I recently
>>> ordered a TICC as well.  By the time I'm done I probably will have
>>> purchased more than a commercial  product, ha!
>> 
>> Jürg Kögel did a redesign of the Riley DMTD earlier this year,
>> which looks very nice. And the measurements I've seen are very
>> impressive (it's on par with the best state of the art I am aware of).
>> So you might want to contact him and see whether he has some board left.
>> 
>> 			Attila Kinali
>> 
>> 
>> [1] "Residual PM Noise Evaluation of Radio Frequecny Mixers"
>> by Barnes, Hati, Nelson, Howe, 2011
>> https://doi.org/10.1109/FCS.2011.5977868
>> http://time.kinali.ch/mixers/residual_pm_noise_evaluation_of_radio_frequency_mixers-2011-barnes_hati_nelson_howe-05977868.pdf
>> 
>> [2] "Tutorial on the double-balanced mixer"
>> by Enrico Rubiola, 2006
>> http://arxiv.org/abs/physics/0608211
>> -- 
>> It is upon moral qualities that a society is ultimately founded. All 
>> the prosperity and technological sophistication in the world is of no 
>> use without that foundation.
>>                -- Miss Matheson, The Diamond Age, Neal Stephenson
>> 
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.