The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator

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A question..
The Timepod still has Wilkinson power splitters, am I right? Did not try to change that?
Just asking because of the very high quality of these tests, ('complimenti'). Scraping the bottom of the barrel, so it could become a factor?

Ciao, George

The Timepod has a pair of Mini-Circuits power splitter, I don't see any reason to replace something in the instrument since it measures exactly like the Aeroflex PN9000 and the Agilent E5052.

Moreover the 3 cornered hat measurement tecnique allows to measure DUT better than the reference (thanks to the cross correlation).

The Timepod is the way to reach the best results but our target is the best audio chain as possible, so no need and no time to tweak the instrument that already does the job as expected.
 
Hi, Andrea,



Congradulations on the fantastic results and thanks for sharing and everything. This really changes the perspective of group buy. I suppose a 5.6448mHz SC cut would be most sort after. I am in for one.



Also, I am thinking to get a 24mHz AT cut for an FPGA project, with simply Pierce or your New Pierce circuit. I suppose it would be wiser to go 24mHZ directly, instead of 6mHZ pierce followed by two doublers? Not sure if there are other interested forumer to meet the MPQ though.



Cheers.





W. YAN

For an FPGA project the AT-Cut crystal is more than enough, difficult to say if there will be enough interest to reach the MOQ, the GB is open.
 
I think Gerhard had explained it very well.
I do recollect that John had mentioned resistive dividers are more noisy but more "honest".
So in response to
so no need and no time to tweak the instrument that already does the job as expected.

Yes, good point. As far as it does not 'Better than expected'.. .;) :D

The TimePod does have MCL Wilkinson type, hybrid differentially terminated power dividers.
Most probably the PhaseStation does not.

But it is really nitpicking, so never mind.

Ciao, George
 
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So in response to

Yes, good point. As far as it does not 'Better than expected'.. .;) :D

I believe that I have said several times that the measuremts of the Timepod have been compared with the ones obtained with the Aeroflex and the E5052.
The result is that the plots are almost identical when measuring the same oscillators, maybe the Timepod is a little pessimistic against the other two gears.

Therefore, again you are free to trust or not the measurements we have done for the community, spending a lot of time.
Moreover you can repeat all the measurements by yourself, I look forward.

But please, keep in mind that me and my co-developer we are not enjoying with LEGO toys, we are trying to develop the best audio system as possible for a hobbyist, without compromises.
So don't be surprised if our oscillators perform at least or maybe better than a 19000 USD device.
 
Yes, good point. As far as it does not 'Better than expected'.. .;) :D

I attach the phase noise plots of the HCD661 OCXO at 11.2896 MHz measured with the Timepod (pink line) and by the manufacturer with the Aeroflex PN9000.

As you can see the plots are almost superimposable, just in case the Timepod is a little pessimistic.

As soon as I find the plot I will also publish the measurement of the same oscillator with the E5052B.

I wonder why you keep questioning the reliability of the measurements of the Timepod.
Just a curiosity.
 

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No, it jumps from C-mode to the B-mode resonance of the SC-cut crystal
which is 10% higher. You need a circuit that is more selective.
(Selectivity that is not in the crystal.) The B-mode resonance can easily
have the same or even better Q, but the TC is ridiculous.

Cheers, Gerhard

Yes, Andrea told me the same thing before . My clock board + oven has been powered up for years, and it runs very hot. The 7812 is constantly over 100C, and the heat will easily transfer to the clock board below. I believe some part value are off the spec already.

Poting
 
Do the OCXOs and the frequency doublers need to be shielded from each other? Can I just put 2 OCXOs and 2 frequency doublers into one, single 1U chassis?

Some pictures about the best way to shield and connect oscillator and frequency doublers.

The longer box is the oscillator, the shorter boxes are the frequency doublers.

Semi-rigid 50 ohm RF cables SMA terminated have been used to connect the devices.
 

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The schematics of the new devices will not be published, sorry but my co-developer does not agree to publish them so I must respect his will.

I will publish soon all the BOMs (for bare boards and semi-finished boards assembly) and assembly intrsuctions.

All the BOMs are in xls format fully compatible to be loaded on Mouser website, just a few click to order.
 
Hello Andrea!

Default The new Pierce oscillator
For those who got At-Cut crystals from the previous batches these are the phase noise plots of the new Pierce oscillators at 5.6448 MHz and 6.144 MHz.

Considering that they are fundamental AT-Cut crystal the phase noise performance are very good, -134 dBc and -140 dBc at 10 Hz from the carrier, they perform better than an OCXO I have bought a few years ago from a professional manufacturer.
Attached Thumbnails
The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator-pierce-xo56448-vs-2x-mti-260-ocxo-shielded-att6db-batt-buf2remvd-c27-270pf-pout-9dbm-png The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator-pierce-xo6144-vs-2x-mti-260-ocxo-shielded-att6db-batt-buf2remvd-c27-270pf-pout-10dbm-png

Hi Andrea!
Goodness...it's been a while since the last time I was here (2016) & I see a lot of fantastic new stuff: measurements and developments - Bravo.

Very interesting (for me personally) was the PN measurement-results above of the Pierce oscillator.
As you know, I personally favor the Pierce osc. due to its simplicity and incredible performance, something your measurements clearly show.

Although Timepod/stable is a great plattform, but it's far out of reach for most diy:ers (expensive :crying:)
Very nice of you to share the measurements :)
Keep up the good work!

Best regards: Alex
 
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Hi Andrea.

It is a VERY much appreciated that you make PN measurements and show the results here - thanx again.

Building high performance oscillators without measurements is like walking around with a blind-fold.
But as mentioned earlier, PN equipments are expensive toys, even the wonderful Timepod :-(

Will you be making an updated version of Pierce Oscillator in the near future?

//Alex
 
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