[time-nuts] Harmonics suppression in ring oscillators
attila at kinali.ch
Sun Mar 22 10:36:30 EDT 2015
On Tue, 17 Mar 2015 11:28:59 +0100
Attila Kinali <attila at kinali.ch> wrote:
> So, how do people keep ring oscillators from oscillating at higher modes?
> So far, my google skills have failed me to turn up any answer.
Ok, sofar i've dug up two papers (and a comment on one) that explicitly
deal with harmonics generation in ring oscillators. One is by Sasaki 
and quite old the other is current enough that it seems applicable today.
Sasaki argues, that process variations between transistors
will prevent harmonics in small rings (see also comments in ),
but cannot be prevented reliably in large rings.
Bushan and Ketchen on the other hand say nothing about harmonics in long
or short rings, but say that the proper startup sequence will inject
only a single edge into the ring.
 "Higher Harmonic Generation in CMOS/SOS Ring Oscillators",
by Nobuo Sasaki, 1982
 "Comments on 'Higher harmonic generation in CMOS/SOS ring oscillators'",
by T.W. Huston, 1983
 "Generation, Elimination and Utilization of Harmonics in Ring Oscillators",
by Manjul Bushan, Mark B. Ketchen, 2010
< _av500_> phd is easy
< _av500_> getting dsl is hard
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