Hi I think you'll find that the low current amps in their schematic have pretty large 1/f noise.
Bob On Aug 10, 2013, at 11:04 AM, Magnus Danielson <mag...@rubidium.dyndns.org> wrote: > On 08/10/2013 12:10 PM, Attila Kinali wrote: >> On Sat, 10 Aug 2013 02:39:35 -0700 >> wb6bnq <wb6...@cox.net> wrote: >> >>> I gather you did not fully read the paper ? >> I did, but... >> >>> This paper presents a circuit topography that allows the low current >>> operation at a high frequency (12.8 MHz) thus reducing complexity. This >>> in turn allows the design and manufacture of a radio system using one >>> crystal oscillator at a frequency of 12.8 MHz (example in the paper) >>> with the low power advantage that previously required two oscillators. >> That's one advantage, and not a small one, but differential oscillators >> have been in use earlier and even in places where power consumption did >> not matter much. It pops up in crystal oscillator designs now and then >> but without any mention why this architecture was choosen. So i started >> to wonder whether there was any additional advantage than just lower >> power consumption and being able to work with less headroom, like better >> phase noise or better long term stability or less harmonics. > Well, at least from this paper they have not analyzed that. Here they > only use it for it's benefits in power, which is obvious from the Abstract. > > If you wish to know other benefits, they need to be analyzed separately, > which by itself might prove an interesting paper. Reducing current drawn > should be interesting, as this should reduce 1/f noise in the feedback > amp, which should make the 1/f^3 noise lower significantly, which should > be beneficial for the stability of the oscillator in noise terms, > however it might not be beneficial for the oscillator in systematic > frequency drift terms. As always, it's a balance thing. > > It should not be too hard to build it, try it, measure it and learn from > it. Sounds like fun! > > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.