kb...@n1k.org said: > If you want to run a fixed / well regulated C Field, a DDS with (say) 48 bits > would allow you to tune the device well past parts in 10^-15.
I don't know how to think about a DDS in this context. I remember years ago thinking that a DDS was the greatest thing since sliced bread. In the context of something like a PPS going into a PC for timekeeping, that's probably true. You get long term accuracy and the PC can't see the short term issues. But then, somebody mentioned close-in spurs. They get closer the more bits you have in the DDS magic number. (What is that number called?) Suppose I have a black box labeled "10 MHz" with a cable coming out. If you plug that cable into your ADEV measuring setup, can you tell if my box has a DDS in it? If you plug that cable into your spectrum analyzer, how good a setup do you need in order to see the spurs? Do they get lost in the close in noise? Or maybe the question should be how clean a signal do I need to start with before the spurs become visible? Or what should I be asking? -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.