[time-nuts] Re: High precision OCXO supplier for end costomers
Am 10.01.2022 um 20:05 schrieb Attila Kinali: On Mon, 10 Jan 2022 19:19:09 +0100 Stefan Heinzmann wrote: Yet you mention phase noise specs very close to the carrier (so close that any artifacts are bound to mix into the subsonic range!), A word of caution here: Human hearing is very very sensitive to some things. One of those is two-tone discrimination. We can tell two simultaneous tones appart quite easily, even if they are very close, given they are at about the same loudness. 10Hz difference is nothing and everyone can do that, even without training. Only once you get to around 1Hz difference, will you need to get a musician or someone with an equally trained ear. And it isn't the limit yet of what we found that people, with training, can hear. When two tones with approximately the same level and a frequency difference of 1 Hz mix, you get a flanging effect due to the shifting phase relationship, and that tends to be very obvious. No need for a trained ear there. But that's not what we're about here. Human hearing definitely has its particular sensitivities, but that only goes to show that you can't make sweeping generalizations that can be expressed in terms of simple numbers like the phase noise 1 Hz from the carrier. It is dependent on the scenario, and one of the questions that needed asking, and was asked, is: What does the oscillator actually drive, i.e. feed into? There simply isn't any way to come up with meaningful figures if you don't have a very clear answer to that question. And the original poster didn't offer any. Furthermore, the ear's properties, and those of the entire auditory system, have been studied in considerable detail. It isn't a big mystery anymore what we are capable of hearing, and what we almost certainly aren't. This includes the effect of phase jitter/noise. The reason why I am sceptical of the phase noise specs is because artifacts would end up at much lower amplitudes. Which means the signal that causes the artifact would be so much louder than the artifact, that it would mask the artifact. Yes, masking is one reason why you wouldn't hear artifacts resulting from phase noise close to the carrier. But the specs offered by the original poster are so "aggressive" that you wouldn't even need to take masking into account for dismissing audible effects as implausible. Cheers Stefan ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: High precision OCXO supplier for end costomers
Hi Norman, I was hoping for an answer that was more quantitative. We're engineers, right? For us, the question is not so much "whether?" but "how much?", and particularly "how much do I need for how much of an effect?". I am especially skeptical of your assertions because you don't seem to address at all how the frequency spectrum of the phase noise impacts the effect. If phase noise does have an effect, I would expect to see a strong dependency here, and Attila has hinted at the reason why this is. Yet you mention phase noise specs very close to the carrier (so close that any artifacts are bound to mix into the subsonic range!), which by all educated reasoning should be the least relevant. So, again, what "hard facts and numbers" do you have available that would allow us to estimate how much degradation is to be expected from a certain performance level of the oscillator, and in what application? And, please, don't assume we're rookies here! The hint that the power supply can be important is quite unnecessary and can very easily be interpreted as offensive. This is not an audiophile mailing list! Cheers Stefan P.S.: By the way, having brought up the topic, you could bolster your reputation by showing how phase noise relates to bit error rate (quantitatively!). Am 10.01.2022 um 18:07 schrieb Norman Reitz via time-nuts: Hi Stefan, Bernd said it allready. If you once notice the result of a "better" clock with lower phase noise, you dont want to miss it anymore. Even if there is a lot of vodoo and pseudo-sciences in the audio sector - and audio-nuts can talk hours about things no scientist ever heard about. But the improvement of phase noise is not an imagination. We are not talking about making something just "work". In worst case, phase noise can lead to bit errors. better/lower phase noise clocks will produce a better musical flow, better dynamics, better representation of details and details that were notbeeing noticed before. And don't forget - the quality of the power supply is not entirely unimportant ;-) kind regards Norman Am Montag, 10. Januar 2022, 15:52:59 MEZ hat Stefan Heinzmann Folgendes geschrieben: I'm curious, too, what kind of audio application requires this level of phase noise performance, and why. Cheers Stefan Am 10.01.2022 um 12:35 schrieb Attila Kinali: On Mon, 10 Jan 2022 08:26:26 + (UTC) Norman Reitz via time-nuts wrote: I am looking for suppliers of high-quality OCXO in 10 Mhz (sine / square) and 25 Mhz sine wave output. Try contacting Bernd Neubig at Axtal. He is a fellow time-nut and likely to be open to supply you with what you need. That said, are yo sure you need such stringend phase noise requirements? It's audio. Nobody is going to hear whether the noise is -60dBc or -80dBc @ 1Hz, much less -120dBc. As you have noticed, what you want is not readily available. There are only a handful OCXO available that reach that level. One of them is the famous Oscilloquartz 8607 and its successor the Rakon HSO13/HSO14. But be prepared to pay the price of a small car for each of them. And there is the NEL ULPN OCXO 1714a, but I don't know how much that one costs. Attila Kinali ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Clock specs for audio (was: High precision OCXO supplier for end costomers)
Just curious: Do you, from your customer interactions, have the impression that your customers are equipped to verify those performance figures? Or do they essentially have to trust you? Cheers Stefan Am 10.01.2022 um 16:12 schrieb Bernd Neubig: We are receiving such inquiries from "Audio nuts" rather frequently, but also from professional high-end audios-studio equipment makers. There argument is often, that the spatial transparency of the sound, i.e. how exactly you can locate the sound source (instrument in an orchestra) would be noticeably improved by such ultra-low noise OCXO sources. So it should be more about time or phase (jitter?) than about frequency As the customer and his belief is "king" at AXTAL - as long as doable and payable - we have developed our AXIOM45ULN series, where the best phase noise option guarantees a PN level of -115 dBc/Hz @ 1 Hz. But this kind of performance can only be achieved by a crystal selection with rather low yield. Therefore, as a manufacturer you need enough customers who accept that "less is sufficient" and will buy the OCXO made from the other crystals. We also are getting a few parts with -120 dBc/Hz @ 1 Hz out of a larger lot, but we rather keep them than selling them to everybody. Best regards Bernd -Ursprüngliche Nachricht- Von: Attila Kinali [mailto:att...@kinali.ch] Gesendet: Montag, 10. Januar 2022 15:42 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] Clock specs for audio (was: High precision OCXO supplier for end costomers) On Mon, 10 Jan 2022 12:35:17 +0100 Attila Kinali wrote: That said, are yo sure you need such stringend phase noise requirements? It's audio. Nobody is going to hear whether the noise is -60dBc or -80dBc @ 1Hz, much less -120dBc. To give here a bit more background: psychoacoustic masking, which is the relevant metric here, mans that we cannot discern sounds that are close to eachother with one of them being louder than the other. Depending on who you listen to, it's usually a sound masking another sound at a distance of 100Hz up to 20dB to 40dB lower. Even if we account for someone with golden ears and use 60dB, that would translate to a noise spec of -60dBc @ 100Hz offset. That's a spec that almost all XO do fulfill. A good VCXO (40-100MHz) is somewhere around 90-100dBc @ 100Hz. Any OCXO will fulfill that spec too, even the tiny DIL-14 ones (most are at -110-140dBc @100Hz @10MHz). And this doesn't take into account that we are arguing about audio frequency specs at HF frequencies. I.e. if we use the 10MHz clock and use it to derive a sampling clock for an ADC to sample a 20kHz signal, the noise performance improves by another ~25dB... at least (if the design is done right, it can be up to 50dB) What is more important than close in noise, though, is broadband noise performance and spurs. For someone with good ears, it's not unheard of to be able to discern far away noise and spurs down a -100dB-120dB. Especially the spurs can be quite hard to control, depending on what clock synthesis system is used. Another important spec, especially for recording, is accuracy of frequency. An offset of just 1ppm becomes 3.6ms if you record for an hour. That's something most people can hear already. But whether this actually elevant or not depends on how the recording is done. The usual way is to have a central master clock that feeds all clocked devices, such that all of them have the same notion of time/frequency. In that case, quite high frequency deviations can be tolerated, way beyond what a simple XO would deliver. Attila Kinali -- In science if you know what you are doing you should not be doing it. In engineering if you do not know what you are doing you should not be doing it. -- Richard W. Hamming, The Art of Doing Science and Engineering ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: High precision OCXO supplier for end costomers
I'm curious, too, what kind of audio application requires this level of phase noise performance, and why. Cheers Stefan Am 10.01.2022 um 12:35 schrieb Attila Kinali: On Mon, 10 Jan 2022 08:26:26 + (UTC) Norman Reitz via time-nuts wrote: I am looking for suppliers of high-quality OCXO in 10 Mhz (sine / square) and 25 Mhz sine wave output. Try contacting Bernd Neubig at Axtal. He is a fellow time-nut and likely to be open to supply you with what you need. That said, are yo sure you need such stringend phase noise requirements? It's audio. Nobody is going to hear whether the noise is -60dBc or -80dBc @ 1Hz, much less -120dBc. As you have noticed, what you want is not readily available. There are only a handful OCXO available that reach that level. One of them is the famous Oscilloquartz 8607 and its successor the Rakon HSO13/HSO14. But be prepared to pay the price of a small car for each of them. And there is the NEL ULPN OCXO 1714a, but I don't know how much that one costs. Attila Kinali ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
