[time-nuts] Re: Clock specs for audio (was: High precision OCXO supplier for end costomers)

[Lux, Jim]

On 1/10/22 7:12 AM, Bernd Neubig wrote:
> 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
>

And I suppose this is why it's worth talking to the mfr than looking 
through the catalogs. There might well be some key requirement that if 
relaxed slightly would work out quite well in terms of availability.

We run into this all the time in the space business - someone does a 
structured requirements flowdown, allocating design margin to subunits, 
and winds up with a performance spec that is difficult to meet, and 
nobody wants to go back up the flowdown chain and ask if the requirement 
can be changed.  Indeed, the cost of doing the waiver might be more than 
just buying the unnecessarily expensive part.