[time-nuts] FW: Injection locking

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Feb 2 20:56:54 UTC 2010

However injection locking also works when the frequencies ratios 
involved are rational numbers.
For 22MHz and 10MHz, the corresponding ratio is 11/5 a rational number.
For 42MHz and 10MHz, the frequency ratio is 21/5 a rational number


Bruce Griffiths wrote:
> To generate either 6MHz or 7MHz from 10MHz one can always use 
> something akin to a conjugate regenerative divider.
> For 7Mhz this requires a mixer a 7MHz bandpass filter, a 3MHz bandpass 
> filter, a couple of power splitter/combiners, and a couple of amplifiers.
> For 6Mhz this requires a mixer a 6MHz bandpass filter, a 4MHz bandpass 
> filter, a couple of power splitter/combiners, and a couple of amplifiers.
> Bruce
> francesco messineo wrote:
>> Hi Murray and all,
>> Yes, indeed injection locking looks very interesting, and I started
>> reading around. Seems relatively easy for 22 MHz, but not as easy for
>> 42 MHz (good values should be 6 or 7 MHz, right?).
>> So far the practical circuit I've seen are few, and this would make me
>> lean in favour of
>> direct synthesys which indeed looks easy but forces me to abandon the
>> old oscillator
>> circuits.
>> In the next days I'll try simulating a few ideas with spice and then 
>> decide.
>> First wild idea: how about making two CMOS gate xtal oscillators with
>> injection locking as you describe? I'd need 2 MHz (10 divided by five)
>> for the 22 MHz, but how practical would be obtaining the 6 or 7 MHz
>> from 10 MHz? It would need another oscillator locked....
>> Thanks
>> Frank IZ8DWF
>> On 2/2/10, Murray Greenman<Murray.Greenman at rakon.com>  wrote:
>>>   -----Original Message-----
>>>   From: Murray Greenman
>>>   Sent: Wednesday, 3 February 2010 9:00 a.m.
>>>   To: 'time-nuts at febo.com'
>>>   Subject: Injection locking
>>>   Frank,
>>>   Bruce's collection would be a good place to start. Thanks Bruce. 
>>> Most of
>>>   the examples relate to microwave applications, where often there 
>>> is no
>>>   alternative, but the approach works well on HF and VHF as well, 
>>> and more
>>>   importantly, can be achieved with existing oscillators with little
>>>   modification. The IL technique works with ratios from 20:1 to 1:20 or
>>>   more, and works well with the GPSDO as a reference.
>>>   My experience is mostly with locking HF crystal oscillators. It works
>>>   with overtone as well as fundamental oscillators. With an overtone
>>>   oscillator you can couple into the mode suppression choke. With a 
>>> tuned
>>>   tank Pierce oscillator you can couple into the output tank. With a
>>>   Colpitts, inject into the emitter, collector, or bottom of the 
>>> crystal.
>>>   I have made an excellent 10MHz CMOS gate oscillator with 2MHz 
>>> injection
>>>   into a varicap acting as one of the crystal load caps (output side).
>>>   Kit VK2LL and others have used 10MHz injection to lock the 20MHz
>>>   reference in common Icom HF transceivers.
>>>   Arguably the father of the Injection Locking technique would be Vasil
>>>   Uzunoglu, and I have some references for articles by him. The most
>>>   readable article is "Synchronous Oscillator outperforms the PLL" 
>>> (from
>>>   EDN 1999) http://www.edn.com/contents/images/46326.pdf. It shows 
>>> how to
>>>   emitter-lock a conventional Colpitts oscillator. The secret here 
>>> is to
>>>   get the bias correct. The test and measurement techniques he uses 
>>> are a
>>>   good way to assess performance. Robert Adler (inventor of the TV
>>>   remote!) also explored the IL technique.
>>>   See:
>>>   http://www.edn.com/contents/images/46326.pdf
>>>   US Patent 4,355,404 "Carrier Recovery Network for QPSK Modems 
>>> employing
>>>   Synchronized Oscillators", Uzunoglu 1982
>>>   US Patent 6,580,330 "Injection Locked Oscillator Automatic Frequency
>>>   Centering method and Apparatus", Katznelson&  Petrovic 2003 (has a 
>>> good
>>>   list of background papers to read)
>>>   "A study of locking oscillators..." Proc IEEE R Adler 1973
>>>   http://ieeexplore.ieee.org/iel5/5/31361/31173/01451222.pdf
>>>   http://en.wikipedia.org/wiki/Injection_locking
>>> http://www.amalgamate2000.com/radio-hobbies/radio/synchronous_oscillator 
>>>   .htm
>>> http://potol.eecs.berkeley.edu/~jr/research/PDFs/2009-01-ASPDAC-Bhansali 
>>>   -Roychowdhury-GenAdler.pdf
>>> http://citeseerx.ist.psu.edu/viewdoc/download?doi= 
>>>   p1&type=pdf
>>>   That should keep you busy for a while!
>>>   73,
>>>   Murray ZL1BPU

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