Re: [time-nuts] injection locking crystal oscillator
Hi a simple example of an injection locked oscillator is the Collins 618T3 avionics HF transceiver. The 3 MHz master crystal oscillator is used to injection lock the lower frequency oscillators such as the 500 KHz source for the unit's IF section. It uses simple off the shelf inductors and a few bi-polar transistors and seems to be a great solution instead of noisy odd-ball dividers. Check it out.Bob, KE6F -Original Message- From: Bill Byrom To: time-nuts Sent: Sat, Mar 2, 2019 5:00 am Subject: Re: [time-nuts] injection locking crystal oscillator In the June 1946 issue of "Proceedings of the I.R.E.", Robert Adler published "A Study of Locking Phenomena in Oscillators*. I believe this is the first full study of injection locking. This paper was so important that it was republished in the October 1973 issue of "Proceedings of the IEEE". This paper give the required condition (under a small signal approximation) for injection synchronization as: (Einj/E) > (2 Q) | delta w / w | (equation 13b) I can't accurately reproduce this equation in plaintext, but it states that the ratio of the injected voltage to natural oscillator voltage must be greater than twice the product of the circuit Q and the absolute value of the fractional frequency error between the injection frequency and natural oscillator frequency. From this equation it would appear that for a large Q (such as 100,000) the lock range of the injection frequency would be much less than +/- 5 ppm, since the injection voltage would normally be much less than the natural oscillator voltage. For lower Q circuits a larger lock range would be available as long as the injection voltage wasn't too weak. Access to the Adler paper from either of the publication dates requires IEEE membership or related credentials, but the principles laid out there are extended in the freely available papers below: ** "A Study of Injection Locking and Pulling in Oscillators" (Behzad Razavi in IEEE Journal of Solid-State Circuits, September 2004) : http://www.seas.ucla.edu/brweb/papers/Journals/RSep04.pdf This paper derives in a different manner "Adler's equation" [ equation (28) in the paper ], which describes the behavior of LC oscillators under injection. This should also be applicable to crystal (and other resonator) oscillators. Section III (Injection Pulling) C (Quasi-lock) describes the behavior when the injection frequency is outside the lock range. Section IV (Requisite Oscillator Nonlinearity) shows that nonlinear behavior in the oscillator is necessary for injection locking to work. Section V (Phase Noise) describes the reduction of the phase noise of an oscillator by a low-noise injection source. Section VI describes the effect of injection pulling on a PLL. ** "Gen-Adler: The Generalized Adler’s Equation for Injection Locking Analysis in Oscillators" (Bhansali and Roychowdhury in IEEE 2009 Asia and South Pacific Design Automation Conference): http://potol.eecs.berkeley.edu/~jr/research/PDFs/2009-01-ASPDAC-Bhansali-Roychowdhury-GenAdler.pdf The second paper listed above uses "Perturbation Projection Vector (PPV)" analysis, which I don't understand. The authors derive a Generalized Adler's equation which is valid for any type of oscillator. Ring oscillators are discussed, and oscillator waveforms are shown when the injection has a sine, square wave, or exponential waveform. I post this in case anyone wants to use an analytical approach to investigating injection locking. -- Bill Byrom N5BB On Fri, Mar 1, 2019, at 9:00 AM, Neil wrote: > I have five systems using injection locking. There are a few issues to > watch. If you inject at too high a level, any noise on the reference > will appear in the oscillator output. I use a 56 ohm resistor to > terminate the reference signal coax input, then a 100pF cap and a series > resistor connected to on leg of the crystal. The resistor value needs > to be selected so I can get a solid pull-in and lock over an > acceptably-wide range. In most cases, I am multiplying the crystal osc > up to 3.3, 5.6 or 10.2 GHz and using a PLL chip driven from an Rb as the > reference to generate 0dBm at the correct locking frequency around 117 > MHz for example. > > If the crystal free-runs close to the lock frequency, say within 200ppb, > the series resistor can be 5k or so, and there is almost no effect on > close-in noise, and no sign of spurs. If I have to pull the crystal > more than about +-500ppb, the resistor needs to be a few hundred ohms, > and the synth noise sidebands start to be seen in the osc output. With > a 70 ohm series resistor, the noise of the osc is only about 10dB down > on the noise of the synth, but the lock-in range is around +-1200 ppb, > slightly more on the LF side. > > When the osc drifts too far away from the reference, or the level is too > low, you get a spread of frequencies out of the oscillator as it tries > to pull into
Re: [time-nuts] injection locking crystal oscillator
Am 02.03.19 um 17:02 schrieb jimlux: Also, since injection locking is a case of coupled oscillators.. you might be interested in this (freely downloadable): Ulrich has a discussion of n promiscously coupled oscillators in [1]. In real life probably a debugging nightmare. I'd like to couple a bunch of MTI-260 oscillators slooowly to a common incoming reference and then Wilkinson the outputs together. A somewhat more "disciplined" approach. I see them shiver with anticipation in the drawer. Need more free time. :-) Gerhard [1] Rohde, Poddar, Böck: The Design of Modern Microwave Oscillators For Microwave Applications, Wiley < https://www.amazon.de/Design-Microwave-Oscillators-Wireless-Applications/dp/0471723428/ref=sr_1_1?ie=UTF8=1551547636=8-1=The+Design+of+modern+Microwave+Oscillators++For+Microwave+Applications. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] injection locking crystal oscillator
Hi Where it gets nasty is when you realize that Q is just an approximation for the phase slope of the oscillator at the operating point……. The Q of a crystal does not change as a function of frequency. The rate of impedance change vs frequency most definitely does. As you approach parallel resonance it gets quite high. This impacts your ability to tune the oscillator. It also impacts your ability to injection lock it. It is the source of the commonly heard comment “easier to injection lock on the low side ….”. Bob > On Mar 2, 2019, at 12:37 AM, Bill Byrom wrote: > > In the June 1946 issue of "Proceedings of the I.R.E.", Robert Adler published > "A Study of Locking Phenomena in Oscillators*. I believe this is the first > full study of injection locking. This paper was so important that it was > republished in the October 1973 issue of "Proceedings of the IEEE". This > paper give the required condition (under a small signal approximation) for > injection synchronization as: > > (Einj/E) > (2 Q) | delta w / w | (equation 13b) > > I can't accurately reproduce this equation in plaintext, but it states that > the ratio of the injected voltage to natural oscillator voltage must be > greater than twice the product of the circuit Q and the absolute value of the > fractional frequency error between the injection frequency and natural > oscillator frequency. From this equation it would appear that for a large Q > (such as 100,000) the lock range of the injection frequency would be much > less than +/- 5 ppm, since the injection voltage would normally be much less > than the natural oscillator voltage. For lower Q circuits a larger lock range > would be available as long as the injection voltage wasn't too weak. > > Access to the Adler paper from either of the publication dates requires IEEE > membership or related credentials, but the principles laid out there are > extended in the freely available papers below: > > ** "A Study of Injection Locking and Pulling in Oscillators" (Behzad Razavi > in IEEE Journal of Solid-State Circuits, September 2004) : > http://www.seas.ucla.edu/brweb/papers/Journals/RSep04.pdf > > This paper derives in a different manner "Adler's equation" [ equation (28) > in the paper ], which describes the behavior of LC oscillators under > injection. This should also be applicable to crystal (and other resonator) > oscillators. > > Section III (Injection Pulling) C (Quasi-lock) describes the behavior when > the injection frequency is outside the lock range. > > Section IV (Requisite Oscillator Nonlinearity) shows that nonlinear behavior > in the oscillator is necessary for injection locking to work. > > Section V (Phase Noise) describes the reduction of the phase noise of an > oscillator by a low-noise injection source. > > Section VI describes the effect of injection pulling on a PLL. > > ** "Gen-Adler: The Generalized Adler’s Equation for Injection Locking > Analysis in Oscillators" (Bhansali and Roychowdhury in IEEE 2009 Asia and > South Pacific Design Automation Conference): > http://potol.eecs.berkeley.edu/~jr/research/PDFs/2009-01-ASPDAC-Bhansali-Roychowdhury-GenAdler.pdf > > The second paper listed above uses "Perturbation Projection Vector (PPV)" > analysis, which I don't understand. The authors derive a Generalized Adler's > equation which is valid for any type of oscillator. Ring oscillators are > discussed, and oscillator waveforms are shown when the injection has a sine, > square wave, or exponential waveform. > > I post this in case anyone wants to use an analytical approach to > investigating injection locking. > > -- > Bill Byrom N5BB > > On Fri, Mar 1, 2019, at 9:00 AM, Neil wrote: >> I have five systems using injection locking. There are a few issues to >> watch. If you inject at too high a level, any noise on the reference >> will appear in the oscillator output. I use a 56 ohm resistor to >> terminate the reference signal coax input, then a 100pF cap and a series >> resistor connected to on leg of the crystal. The resistor value needs >> to be selected so I can get a solid pull-in and lock over an >> acceptably-wide range. In most cases, I am multiplying the crystal osc >> up to 3.3, 5.6 or 10.2 GHz and using a PLL chip driven from an Rb as the >> reference to generate 0dBm at the correct locking frequency around 117 >> MHz for example. >> >> If the crystal free-runs close to the lock frequency, say within 200ppb, >> the series resistor can be 5k or so, and there is almost no effect on >> close-in noise, and no sign of spurs. If I have to pull the crystal >> more than about +-500ppb, the resistor needs to be a few hundred ohms, >> and the synth noise sidebands start to be seen in the osc output. With >> a 70 ohm series resistor, the noise of the osc is only about 10dB down >> on the noise of the synth, but the lock-in range is around +-1200 ppb, >> slightly more on the LF side. >> >> When
Re: [time-nuts] injection locking crystal oscillator
On 3/1/19 9:37 PM, Bill Byrom wrote: In the June 1946 issue of "Proceedings of the I.R.E.", Robert Adler published "A Study of Locking Phenomena in Oscillators*. I believe this is the first full study of injection locking. This paper was so important that it was republished in the October 1973 issue of "Proceedings of the IEEE". This paper give the required condition (under a small signal approximation) for injection synchronization as: (Einj/E) > (2 Q) | delta w / w | (equation 13b) Also, since injection locking is a case of coupled oscillators.. you might be interested in this (freely downloadable): https://descanso.jpl.nasa.gov/monograph/series11_chapter.html Coupled-Oscillator Based Active-Array Antennas - Ronald J. Pogorzelski - Apostolos Georgiadis ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] injection locking crystal oscillator
In the June 1946 issue of "Proceedings of the I.R.E.", Robert Adler published "A Study of Locking Phenomena in Oscillators*. I believe this is the first full study of injection locking. This paper was so important that it was republished in the October 1973 issue of "Proceedings of the IEEE". This paper give the required condition (under a small signal approximation) for injection synchronization as: (Einj/E) > (2 Q) | delta w / w | (equation 13b) I can't accurately reproduce this equation in plaintext, but it states that the ratio of the injected voltage to natural oscillator voltage must be greater than twice the product of the circuit Q and the absolute value of the fractional frequency error between the injection frequency and natural oscillator frequency. From this equation it would appear that for a large Q (such as 100,000) the lock range of the injection frequency would be much less than +/- 5 ppm, since the injection voltage would normally be much less than the natural oscillator voltage. For lower Q circuits a larger lock range would be available as long as the injection voltage wasn't too weak. Access to the Adler paper from either of the publication dates requires IEEE membership or related credentials, but the principles laid out there are extended in the freely available papers below: ** "A Study of Injection Locking and Pulling in Oscillators" (Behzad Razavi in IEEE Journal of Solid-State Circuits, September 2004) : http://www.seas.ucla.edu/brweb/papers/Journals/RSep04.pdf This paper derives in a different manner "Adler's equation" [ equation (28) in the paper ], which describes the behavior of LC oscillators under injection. This should also be applicable to crystal (and other resonator) oscillators. Section III (Injection Pulling) C (Quasi-lock) describes the behavior when the injection frequency is outside the lock range. Section IV (Requisite Oscillator Nonlinearity) shows that nonlinear behavior in the oscillator is necessary for injection locking to work. Section V (Phase Noise) describes the reduction of the phase noise of an oscillator by a low-noise injection source. Section VI describes the effect of injection pulling on a PLL. ** "Gen-Adler: The Generalized Adler’s Equation for Injection Locking Analysis in Oscillators" (Bhansali and Roychowdhury in IEEE 2009 Asia and South Pacific Design Automation Conference): http://potol.eecs.berkeley.edu/~jr/research/PDFs/2009-01-ASPDAC-Bhansali-Roychowdhury-GenAdler.pdf The second paper listed above uses "Perturbation Projection Vector (PPV)" analysis, which I don't understand. The authors derive a Generalized Adler's equation which is valid for any type of oscillator. Ring oscillators are discussed, and oscillator waveforms are shown when the injection has a sine, square wave, or exponential waveform. I post this in case anyone wants to use an analytical approach to investigating injection locking. -- Bill Byrom N5BB On Fri, Mar 1, 2019, at 9:00 AM, Neil wrote: > I have five systems using injection locking. There are a few issues to > watch. If you inject at too high a level, any noise on the reference > will appear in the oscillator output. I use a 56 ohm resistor to > terminate the reference signal coax input, then a 100pF cap and a series > resistor connected to on leg of the crystal. The resistor value needs > to be selected so I can get a solid pull-in and lock over an > acceptably-wide range. In most cases, I am multiplying the crystal osc > up to 3.3, 5.6 or 10.2 GHz and using a PLL chip driven from an Rb as the > reference to generate 0dBm at the correct locking frequency around 117 > MHz for example. > > If the crystal free-runs close to the lock frequency, say within 200ppb, > the series resistor can be 5k or so, and there is almost no effect on > close-in noise, and no sign of spurs. If I have to pull the crystal > more than about +-500ppb, the resistor needs to be a few hundred ohms, > and the synth noise sidebands start to be seen in the osc output. With > a 70 ohm series resistor, the noise of the osc is only about 10dB down > on the noise of the synth, but the lock-in range is around +-1200 ppb, > slightly more on the LF side. > > When the osc drifts too far away from the reference, or the level is too > low, you get a spread of frequencies out of the oscillator as it tries > to pull into lock, but doesn't make it. As the lock level rises, it > pulls closer in, but still with a spread of frequencies until it finally > jumps into lock. There is considerable hysteresis, so check thoroughly > that it will pull in under all likely conditions of voltage and temperature. > > Remember that the coax lead is going to have a major influence on the > oscillator, so keep it short and watch for mechanical vibration or > ringing or temperature variation effects on the cable. Make certain the > connectors are torqued well. If there is a trimmer on the
