-----Original Message----- From: Murray Greenman Sent: Wednesday, 3 February 2010 9:00 a.m. To: '[email protected]' 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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
