Hi On Aug 10, 2013, at 6:29 AM, Charles Steinmetz <[email protected]> wrote:
> I wrote: > >> All of these solutions are for feeding the external reference inputs of >> various test equipment, radios, etc., not for buffering and isolating >> signals for serious phase noise or ADEV analysis. > >> By the time you design a PC card and have it made, you are way, way beyond >> "not a lot of effort" for lots of people, to say nothing of the metalwork >> (even if it is just making new front and back plates for an existing Extron >> box). I can do all of that, and I did, but it appears from the on-list >> interest in video DAs that a lot of time nuts would rather not be bothered. > > I guess what I'm saying is if one is going to the effort to build a DA from > scratch, why build something that is just adequate to distribute a reference > signal to test equipment and radios? Why not really do it right, and build > something that *is* capable of buffering and isolating signals for serious > phase noise and ADEV analysis? > Hi A couple of reasons: 1) You have already gone into or towards the "don't know / can't do" region with a simple pcb and putting a dozen or so holes in a Hammond box. If you add the complexity of a full blown uber circuit you are much further into that area. If you have lost the entire crowd with an afternoon project, there's little use in talking about a two week project. 2) To do an apples to apples type comparison. The super circuits come up and get compared to the modified DA's. The real comparison circuit is much less complex and pretty easy to design. 3) In general you have one "best source" for phase noise and another for ADEV. Except in the case of a Cs, and tau's > 100 seconds, I've never seen them used as the house standard. The standard gets run to things like counters and signal generators mostly to keep them on frequency. In the case of a Cs, the ones I use have multiple outputs already. 4) Overkill is an issue here. Even if it's TimeNuts, there is a point where "good enough" is indeed a measurable quantity. A counter only needs a standard that's good to some level, past that it does no better. The same is true of everything I have hooked up to my standard lines. I have a *lot* of standard lines running around the basement …. Bob > Best regards, > > Charles > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
