[time-nuts] quartz oscillator injection locking

Bob Camp kb8tq at n1k.org
Sat Jul 19 21:06:23 EDT 2014


HI

As long as you have a really poor crystal oscillator (wide band loop) they are quite easy to lock. If you have a high performance crystal oscillator (high Q / narrow band loop) they are relatively difficult to lock. If you are trying to *guarantee* a lock bandwidth and *guarantee* a level of performance they are not an easy way to go. A PLL probably will do what you want with a lot fewer headaches. 

If you want absolute super performance multiplying, then by all means go with the approach. Plan on building a very good OCXO and then having it guarantee good locked performance over a really narrow ( think ppb to less than ppb) sort of range.

Bob

On Jul 19, 2014, at 4:45 PM, paul swed <paulswedb at gmail.com> wrote:

> Attilla I did look at some of the documents. But none showed practical HF
> class injection locking. Say as an example a 6 MHz xtal to a 1 or 2 MHz
> reference.
> It maybe as easy as a single transistor in the oscillators ground lead.
> Always on till a brief pulse from the 1 or 2 MHz ref cuts it off. I think I
> just talked myself into an attempt.
> Regards
> Paul
> WB8TSL
> 
> 
> On Sat, Jul 19, 2014 at 7:23 AM, Attila Kinali <attila at kinali.ch> wrote:
> 
>> On Tue, 24 Jun 2014 21:18:20 +0200
>> Francesco Messineo <francesco.messineo at gmail.com> wrote:
>> 
>>> what would be the best method to try injection locking a butler common
>>> base crystal oscillator (see figure in
>>> http://www.eska.dk/oscillator_data.htm for schematic)?
>>> Any comment about close-in phase noise performance when adding
>>> injection locking to such oscillators?
>>> Thanks in advance for any hint.
>> 
>> Moin,
>> 
>> I cannot give you performance data, but i can point you at some papers
>> that deal with injection locking.
>> 
>> Probably one of the best known papers is from Robert Adler[1].
>> It mainly deals with how locking comes to be, what the conditions
>> for locking are and how to calculate those.
>> 
>> The other big name in injection locking is Kurokawa Kaneyuki.
>> His first paper [2] deals, as the title suggests, with noise in
>> coupled oscillators vs noise in single oscillators.
>> His second paper [3] deals with injection locking itself, similar
>> to what Adler did, but with a more "modern" terminology, but also
>> with more math.
>> (There are more papers from him on this topic, but i have not had
>> time to read those)
>> 
>> Chang et al. did a nice work on locking of multiple oscillators in [4]
>> and how coupling directions affect them.
>> 
>> Razavi did a nice rework of earlier findings on injection locking in [5].
>> In my opinion, this has one of the easier understandable math in all the
>> papers i've read on injection locking. Also his liberal use of graphs
>> simplify the interpretation of the formulas.
>> 
>> Zhang et al. did a quite nice analysis of noise behavoir of coupled
>> oscillators in [6]. But my main reason for mentioning it here is
>> the measurements they made, which might give you an indiciation on where
>> you might end up with your circuit.
>> 
>> If you are more on the simulation side, [7] might give you a point to
>> start how to model injection locking in spice (though, i must say that
>> is one paper i stumbled upon and probably not the best in that area).
>> 
>> HTH
>> 
>>                        Attila Kinali
>> 
>> 
>> [1] "A Study of Locking Phenomena in Oscillators", by Robert Adler, 1946
>> reprinted in Proceedings of IEEE October 1973
>> 
>> [2] "Noise in Synchronized Oscillators", by Kurokawa Kaneyuki, 1968
>> 
>> [3] "Injection Locking in Microwave Solid-State Oscillators", by Kurokawa
>> Kaneyuki, 1973
>> 
>> [4] "Phase Noise in Coupled Oscillators: Theory and Experiment",
>> by Chang, Cao, Mishra and York, 1997
>> 
>> [5] "A Study of Injection Locking and Pulling in Oscillators", by Behzad
>> Razavi, 2004
>> 
>> [6] "A Theoretical and Experimental Study of the Noise Behavior of
>> Subharmonically Injection Locked Local Oscillators", by Zhan, Zhou,
>> and Daryoush, 1992
>> 
>> [7] "Capturing Oscillator Injection Locking via Nonlinear Phase-Domain
>> Macromodels",
>> by Lai and Roychowdhury, 2004
>> 
>> --
>> I pity people who can't find laughter or at least some bit of amusement in
>> the little doings of the day. I believe I could find something ridiculous
>> even in the saddest moment, if necessary. It has nothing to do with being
>> superficial. It's a matter of joy in life.
>>                        -- Sophie Scholl
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