[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
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=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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