[time-nuts] FW: Injection locking

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Feb 2 20:46:00 UTC 2010


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=10.1.1.130.2535&rep=re
>>   p1&type=pdf
>>
>>   That should keep you busy for a while!
>>
>>   73,
>>   Murray ZL1BPU
>>
>>
>>
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>>      
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