We all assumed that.
At least I have designed the analog part of the actual flight hardware for the ISS to link a hydrogen Maser (for short time stability) to a Cesium (it's simply the law for long time stability). That included an xtal osc for the DMTD setup. And yes, I'm not qualified to solder that stuff. I had to call the solder lady who had to re-qualify each year to exchange a part that was "select on test". Only a single change allowed, and that required some paperwork.
And then there are these publications in Microwave Magazine where the circuits are oh so precise and are 200% the same as their simulation. You build them just like published and they not even hit the right overtone. Ooohps, not modelled.
< Colp_layout | Gerhard Hoffmann | Flickr >
< colp_board | Gerhard Hoffmann | Flickr >
< colp_nobuf_60 | Gerhard Hoffmann | Flickr >
Then you are expected to believe the lyrics that describe how close the phase noise simulation matches the FSUP?
Gerhard
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Then it's quite curious that Rakon has used the Timepod to make the measurement.
Please, define "the close to carrier noise", it's not clear what do you mean.
-130dBc at what offset from the carrier?
Not curious at all, it's the references and the DUT that have to be cared of, as described in the quote, for such measurements, something you are not doing, while still claiming performance in that range.
How "close to the carrier", I'll let you define the limits of the "close in phase noise" for the Rakon oscillator.
How "close to the carrier", I'll let you define the limits of the "close in phase noise" for the Rakon oscillator.
Well, so you think that cross correlation could improve the phase noise performance if the references and the DUT are not cared as you have pointed out.
I believe the opposite but I'm open to your demonstation.
And let define the limits of the "close in phase noise" at 0.5Hz from the carrier.
The Rakon is -123dBc and the DRIXO is -114dBc at 0.5Hz from the carrier, so no problem of particular care since the measured phase noise is well below -130dBc.
Finally, the DRIXO oscillator have been measured and the measurement was confirmed from Joseph K who have used a different tool, so you should demonstrate the double measurement is not reliable rather than claim so.
For what its worth here is a really good primer on measuring phase noise https://www.nist.gov/system/files/documents/calibrations/pfc-2.pdf with info on how to use a time interval analyzer and convert from time to spectral density. Way more math than I can comprehend but quite clear otherwise. And it seems I can use my HP5370 to measure phase noise ultimately with the DMTD setup. Maybe someday.
I didn’t “think” anything and I am not about to provide any “demonstration”. I just quoted from multiple sources. Between a defended phd thesis plus peer reviewed published papers and your posts on a hobby forum on the internet, guess who has more credibility.
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But whats the critique then? There seems no way that Andrea could measure better Phase noise results (only worse) by not following the correct procedure. Or do i miss something?
Also feel like I'm missing something (maybe that's the point).
The quote doesnt define the frequency, it comes from a credible source but seems useless for trying to make that point. Just between 1Hz and 0.1Hz there is a huge difference, both 'close in'.
Then maybe those who were mocked for paying extra attention to vibration and heat were on the right track after all?
The quote doesnt define the frequency, it comes from a credible source but seems useless for trying to make that point. Just between 1Hz and 0.1Hz there is a huge difference, both 'close in'.
Then maybe those who were mocked for paying extra attention to vibration and heat were on the right track after all?
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Quite simple: he has built a poor oscillator by his own measurements and therefore he don't accept someone can do better.
So he still keep confuting our measurements even if they were confirmed by a different tool.
In fact he keeps throwing documents at random without any contextualization.
Don't worry, it's his usual behavior.
So he still keep confuting our measurements even if they were confirmed by a different tool.
In fact he keeps throwing documents at random without any contextualization.
Don't worry, it's his usual behavior.
No critique, just wondering how Andrea could measure phase noise at those levels WITHOUT the extra precautions mentioned is several credible references.
Andrea, I have to re-iterate my few days old request: please stop insulting the experience and knowledge of everybody disagreeing with you. I know, you don't consider your stances as an insult, but according to everybody around that attempted a dialogue with you, after expressing any disagreements with your claims, they are.
Andrea, I have to re-iterate my few days old request: please stop insulting the experience and knowledge of everybody disagreeing with you. I know, you don't consider your stances as an insult, but according to everybody around that attempted a dialogue with you, after expressing any disagreements with your claims, they are.
It's not possible to measure the exact values but the measurements are as close as it gets with quite expensive tools. My point is, that with better measurement techniques it's pretty certain that results would improve (probably marginaly but anyhow the results are not gonna get worse) so Andrea is actually claiming worse than the real phase noise results would be by "proper" measurement - No wondering necessary 😉
Edit: Or did i missunderstand and you wanted to imply the plots are faked
Edit: Or did i missunderstand and you wanted to imply the plots are faked
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Sorry but there was no insult from me.
You have published the phase noise plot of the oscillator you have built and it was very poor.
No doubts, just facts.
Ok, because you raised this multiple times, each time misconstruing what was said then on this topic, let's clarify it:
- I've build a fractional PLL (for an non audio application) and happened to post the results here: https://www.diyaudio.com/forums/dig...itter-crystal-oscillator-350.html#post6621426 as an example of phase noise measurement without a timepod.
- The results -110dBrad^2 @1Hz and -124dB @ 10Hz is not too bad given the requirements I had to implement for a ham friend (yes, I do build and give out for free (including shipping!) some of my stuff, as several members on this forum can certify). Actually, this
is worse than your oscillator by about the same amount yours is worse compared to the Rakon oscillators.
- I have never intended to compete with anything that you are selling around, and clearly stated that from the very beginning. I can't interpret you bringing up periodically these old results other than a shameful attempt to discredit my knowledge and experience.
So please stop building straw mans and misconstruing what other people are saying and doing. I would also kindly remind you that only in the few couple of weeks you were asked legitimate questions by several obviously qualified members, and you conveniently skipped the answers, while instead promoting the same type of discrediting tactics, re-iterating ad nauseum a honest mistake that was made. If you need a refresh of these questions, I can come up with quotes and links, let me know. It would help a lot if you could take a technical challenges and questions at face value, rather than interpreting it like somebody is trying to compete with you.
- I've build a fractional PLL (for an non audio application) and happened to post the results here: https://www.diyaudio.com/forums/dig...itter-crystal-oscillator-350.html#post6621426 as an example of phase noise measurement without a timepod.
- The results -110dBrad^2 @1Hz and -124dB @ 10Hz is not too bad given the requirements I had to implement for a ham friend (yes, I do build and give out for free (including shipping!) some of my stuff, as several members on this forum can certify). Actually, this
is worse than your oscillator by about the same amount yours is worse compared to the Rakon oscillators.
- I have never intended to compete with anything that you are selling around, and clearly stated that from the very beginning. I can't interpret you bringing up periodically these old results other than a shameful attempt to discredit my knowledge and experience.
So please stop building straw mans and misconstruing what other people are saying and doing. I would also kindly remind you that only in the few couple of weeks you were asked legitimate questions by several obviously qualified members, and you conveniently skipped the answers, while instead promoting the same type of discrediting tactics, re-iterating ad nauseum a honest mistake that was made. If you need a refresh of these questions, I can come up with quotes and links, let me know. It would help a lot if you could take a technical challenges and questions at face value, rather than interpreting it like somebody is trying to compete with you.
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So your only problem is that your clock seems to measure worse and that Andrea was not nice to you about it?
I would be interested in the open questions btw. ( Sounds sarcastic but it really isnt)
Greetings Oli
I would be interested in the open questions btw. ( Sounds sarcastic but it really isnt)
Greetings Oli
Firstly our DRIXO at 5.6448 MHz has the same phase noise of the Rakon at 10 Hz from the carrier: -155dBc.
It's 8-9 dB worse at 1Hz from the carrier (random walk of the crystal) and it has 12-13 db better noise floor.
Yours is 12dB worse than our 6.144 MHz DRIXO at 1Hz from the carrier (122 vs 110 dBc) and 23 dB worse at 10 Hz from the carrier (147 vs 124dBc).
So not quite the same amount our is worse compared to the Rakon oscillators.
Honestly I don't care much about the above comparison.
But I keep to remark this fact all the times you will claim that the measurements are not reliable (without any proof).
You consider the above facts like an insult just like I consider an insult when you claim the unreliability of my measurements (and Joseph K's measurements).
So if you want to get me stopping repeat, just stop questioning the measurements (without any proof).
Otherwise I have the same rights as you on this forum to reply to your insults.
See what I mean? This is a perfect example of what I am trying to convey.
You claimed for months now that the broadband noise of your oscillator is irrelevant (since you were shown better oscillators in this respect, and you also claimed the broadband noise degradation of the sine to square converter (9-12dB in your case) is also irrelevant), and it is only the 1Hz close in phase noise that matters (for audio) and now it appears the 1Hz close in phase noise is no longer that important, but the phase noise floor is critical, etc... A moving target, while you are trashing everything that comes in your way.
Otherwise said, "if you don't want to be insulted, you better shut up". Nice try, and BTW, the burden of proof is on you. Nobody could prove a negative.
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No, but improper measurement conditions, according to the best practices, can lead to whatever (better or worse) results, depending on the time of day, temperature, season, and the moon phase.
There's more to measurements, in particular at these levels, that a nice plot presented as the absolute truth. There's error sources analysis, value certitude ranges, 3rd party validation (and no, the cheerleader crowd is not a valid 3rd party), independent labs etc... Not to mention the very basic requirement to correlate the measurement results with a final product performance metric, this is for the consumer market, not for a satellite tracking system.
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