Hi > On Jan 7, 2018, at 8:02 AM, Ulrich Rohde via time-nuts <time-nuts@febo.com> > wrote: > > This and related topics are presented in : > > > [BOOK] The design of modern microwave oscillators for wireless applications: > theory and optimizationUL Rohde, AK Poddar, G Böck - 2005 - books.google.com > Delivering the best possible solution for phase noise and output power > efficiency in > oscillators This complete and thorough analysis of microwave oscillators > investigates all > aspects of design, with particular emphasis on operating conditions, choice > of resonators > and transistors, phase noise, and output power. It covers both bipolar > transistors and FETs. > Following the authors' guidance, readers learn how to design microwave > oscillators and … > Cited by 198 Related articles All 6 versions > > > > > 73 de Ulrich , N1 UL
…. There’s also a few papers out there on the topic. I seem to remember sitting through a few you wrote . Bob > In a message dated 1/7/2018 7:07:56 AM Eastern Standard Time, > donaldbcol...@gmail.com writes: > > > Does any limiter, soft or hard, [and perhaps any nonlinearity of power > term 3 or greater in the amplifier of an oscillator] cause the "baseband > 1/f noise to translate up to the resonator frequency [a form of > crossmodulation]?. I wonder this because > phase noise vs freq plots look a bit like the 1/f plots of a resistor, or > active device, or power supply. Ceramic caps, and resonators [I`m thinking > of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise > is associated with dc passing through resistors, or semiconductors. So the > best way to go might be to have a very linear amplifier, which exhibits > very low noise [perhaps 150dB below the operating level], with an AGC loop, > that sets the operating levela little below the level at which the amp > starts to clip - this could be done with a thermistor to avoid the AGC loop > altering the [optimised] operating conditions of the amp. Alternatively you > might be able to use a tetrode device like a dual gate MOSFET, and apply > the AGC to the second gate. Thus you could keep the extremely linear amp > extremely linear. [150dB below 1Volt RMS is 0.032uV RMS]. > Cheers!........................................................................................................................................................................Don > ZL4GX > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virus-free. > www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoo...@gmail.com> wrote: > >> One point about oscillator design I've not yet seen mentioned is this: the >> limiter >> must not degrade the resonator Q when in action. Hence, a pair of diodes >> connected in parallel back to back, across a shunt resonator, would be a >> bad >> thing to do from the perspective of low phase noise. A differential >> amplifier >> that limits by running out of current on peaks, driving a shunt resonator, >> is >> a much better way even though one pays a price in having more transistor >> noise in the circuit. >> >> I've long wondered if a very slow AGC might avoid the nonlinear mechanisms >> issue except, of course, for things happening within the AGC loop's >> bandwidth. >> Is anybody reading this aware of what the truth really is? >> >> Dana >> >> >> On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson < >> mag...@rubidium.dyndns.org >>> wrote: >> >>> >>> >>> On 01/06/2018 10:31 PM, Joseph Gwinn wrote: >>>>> ------------------------------ >>>>> >>>>> Message: 2 >>>>> Date: Sat, 6 Jan 2018 09:19:31 -0500 >>>>> From: Bob kb8tq <kb...@n1k.org> >>>>> To: Discussion of precise time and frequency measurement >>>>> <time-nuts@febo.com> >>>>> Subject: Re: [time-nuts] AM vs PM noise of signal sources >>>>> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org> >>>>> Content-Type: text/plain; charset=utf-8 >>>>> >>>>> Hi >>>>> >>>>> The key point missing is the fact that any real oscillator must have >>>>> a limiter >>>>> in the loop. Otherwise it will “create one” by going over the max >>>>> output of this or >>>>> that amplifier. To the degree that the limiter has issues (limits >>>>> poorly) you will get >>>>> AM noise. >>>> >>>> Hmm. Not strictly true. One can also use an AGC loop, like a wein >>>> bridge oscillator. That said, some kind of softish limiter is commonly >>>> used. >>> >>> Regardless what non-linear mechanism in play, this remains a non-linear >>> mechanism that achieves the goal. Choose wisely. >>> >>> Cheers, >>> Magnus >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>> mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.