On Wed, 28 Apr 2021 13:05:32 +1000, Clifford Heath <no.spam@please.net> wrote:>On 28/4/21 5:35 am, John Larkin wrote: >> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? > >Accidentally? > >:)I just posted an accidental 3 GHz phemt oscillator. Purely fiddled in Spice in a few minutes; all instinct, no theory at all. Reasonably good sine wave. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
GHz oscillator
Started by ●April 27, 2021
Reply by ●April 28, 20212021-04-28
Reply by ●April 28, 20212021-04-28
Clifford Heath <no.spam@please.net> wrote:> On 28/4/21 5:35 am, John Larkin wrote: >> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? > > Accidentally? > > :)Amplifiers will oscillate. Oscillators won't.
Reply by ●April 28, 20212021-04-28
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:> onsdag den 28. april 2021 kl. 01.52.32 UTC+2 skrev John Larkin: >> On Tue, 27 Apr 2021 16:10:37 -0700 (PDT), Lasse Langwadt Christensen >> <lang...@fonz.dk> wrote: >> >> >tirsdag den 27. april 2021 kl. 21.35.27 UTC+2 skrev John Larkin: >> >> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? I >> >> don't need extreme accuracy, and I'd like maybe 1 volt p-p. >> >> >> >> I was thinking a cheap MMIC with PCB delay line feedback. >> >> >> >> MiniCircuits VCOs are around $20, which isn't bad. >> >> >> >> The output would go into a PWM modulator and then an AC-coupled >> >> communications channel. >> > >> >https://www.analog.com/en/products/hmc384.html#product-overview ? >> > >> >$330 development board for a $7 part, it must be plated with platinum >> $7 is cheap for anything Hittite! > > sure, but the $330 board is basically just the part and two sma connectorsPricing of evaluation boards, and even more of "educational" boards, is sometimes very interesting. They can be very expensive or ridiculously cheap. Check the ADALM-PLUTO... it can probably do this function and some of the functions required in addition to that oscillator as well. But it costs much less than that, even though it has many more components.
Reply by ●April 28, 20212021-04-28
"John Larkin" wrote in message news:vapg8g56dptb7moktkh53usv391uiq2cde@4ax.com...>What's a good way to make a, say 2 or 3 GHz sinewave oscillator? I >don't need extreme accuracy, and I'd like maybe 1 volt p-p.Why not a synthetizer/VCO chip, like the ADF4351 and a small MCU to initialize it ? If you prefer a ready-made version, you'll find boards with the synth chip and a nice TFT for 40$ or so on ebay... Output power is a couple of mW. Robert Lacoste ALCIOM - The mixed signal experts - www.alciom.com
Reply by ●April 28, 20212021-04-28
On Wed, 28 Apr 2021 12:31:54 +0200, "Robert Lacoste" <see-alciom-dot-com@none.com> wrote:>"John Larkin" wrote in message >news:vapg8g56dptb7moktkh53usv391uiq2cde@4ax.com... >>What's a good way to make a, say 2 or 3 GHz sinewave oscillator? I >>don't need extreme accuracy, and I'd like maybe 1 volt p-p. > >Why not a synthetizer/VCO chip, like the ADF4351 and a small MCU to >initialize it ? If you prefer a ready-made version, you'll find boards with >the synth chip and a nice TFT for 40$ or so on ebay... Output power is a >couple of mW.I don't have a specific application, but I was hoping for something simple. It's just a shower problem at this point. The general problem is to push a DC-coupled baseband signal of bandwidth B, over a typical comm channel, like a twisted pair with magnetics on both ends, or a fiber with cheap tosa/rosa things on the ends, ac coupled with bandwidth 2 or 3 times B and basically a comparator as the receiver, maybe a poorly defined AGC. One idea is to start with a 2 or 3 GHz oscillator and PWM it. That should be easy to generate and easy to detect. FM is more work. PCM much more. Just thinking. A little phemt or MMIC oscillator won't cost much more than a dollar.> >Robert Lacoste >ALCIOM - The mixed signal experts - www.alciom.com-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Reply by ●April 28, 20212021-04-28
jlarkin@highlandsniptechnology.com wrote:> On Wed, 28 Apr 2021 13:05:32 +1000, Clifford Heath > <no.spam@please.net> wrote: > >> On 28/4/21 5:35 am, John Larkin wrote: >>> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? >> >> Accidentally? >> >> :) > > I just posted an accidental 3 GHz phemt oscillator. > > Purely fiddled in Spice in a few minutes; all instinct, no theory at > all. Reasonably good sine wave. > > >Ungodly amount of gate current, though--abs max is 2 mA. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●April 28, 20212021-04-28
On Wed, 28 Apr 2021 13:37:13 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>jlarkin@highlandsniptechnology.com wrote: >> On Wed, 28 Apr 2021 13:05:32 +1000, Clifford Heath >> <no.spam@please.net> wrote: >> >>> On 28/4/21 5:35 am, John Larkin wrote: >>>> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? >>> >>> Accidentally? >>> >>> :) >> >> I just posted an accidental 3 GHz phemt oscillator. >> >> Purely fiddled in Spice in a few minutes; all instinct, no theory at >> all. Reasonably good sine wave. >> >> >> > >Ungodly amount of gate current, though--abs max is 2 mA.Good point; that's fixable.> >Cheers > >Phil HobbsI'd prefer to use a MMIC, but there seem to be no spice models for mmics. Mini-Circuits was adamant that they would never have spice models for theirs. I guess I've complained about that enough times, so I should make some. The model will be easy but validating will be a pain. I'm thinking of a BFT25 darlington, then tweaked to match reality. ERA-1 to start maybe. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Reply by ●April 28, 20212021-04-28
On Wed, 28 Apr 2021 14:09:37 -0700, jlarkin@highlandsniptechnology.com wrote:>On Wed, 28 Apr 2021 13:37:13 -0400, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote: > >>jlarkin@highlandsniptechnology.com wrote: >>> On Wed, 28 Apr 2021 13:05:32 +1000, Clifford Heath >>> <no.spam@please.net> wrote: >>> >>>> On 28/4/21 5:35 am, John Larkin wrote: >>>>> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? >>>> >>>> Accidentally? >>>> >>>> :) >>> >>> I just posted an accidental 3 GHz phemt oscillator. >>> >>> Purely fiddled in Spice in a few minutes; all instinct, no theory at >>> all. Reasonably good sine wave. >>> >>> >>> >> >>Ungodly amount of gate current, though--abs max is 2 mA. > >Good point; that's fixable. > >> >>Cheers >> >>Phil Hobbs > >I'd prefer to use a MMIC, but there seem to be no spice models for >mmics. Mini-Circuits was adamant that they would never have spice >models for theirs.They specify the S-parameters so you can figure out how much more phase shift is needed on the desired frequency to satisfy the Barkhausen criterion. Of course you have to check that the forward gain is larger than feedback network losses to have a sustained oscillation at desired frequency.> >I guess I've complained about that enough times, so I should make >some. The model will be easy but validating will be a pain. > >I'm thinking of a BFT25 darlington, then tweaked to match reality. >ERA-1 to start maybe.
Reply by ●April 28, 20212021-04-28
On 2021-04-28 23:46, upsidedown@downunder.com wrote:> On Wed, 28 Apr 2021 14:09:37 -0700, jlarkin@highlandsniptechnology.com > wrote: > >> On Wed, 28 Apr 2021 13:37:13 -0400, Phil Hobbs >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >>> jlarkin@highlandsniptechnology.com wrote: >>>> On Wed, 28 Apr 2021 13:05:32 +1000, Clifford Heath >>>> <no.spam@please.net> wrote: >>>> >>>>> On 28/4/21 5:35 am, John Larkin wrote: >>>>>> What's a good way to make a, say 2 or 3 GHz sinewave oscillator? >>>>> >>>>> Accidentally? >>>>> >>>>> :) >>>> >>>> I just posted an accidental 3 GHz phemt oscillator. >>>> >>>> Purely fiddled in Spice in a few minutes; all instinct, no theory at >>>> all. Reasonably good sine wave. >>>> >>>> >>>> >>> >>> Ungodly amount of gate current, though--abs max is 2 mA. >> >> Good point; that's fixable. >> >>> >>> Cheers >>> >>> Phil Hobbs >> >> I'd prefer to use a MMIC, but there seem to be no spice models for >> mmics. Mini-Circuits was adamant that they would never have spice >> models for theirs. > > They specify the S-parameters so you can figure out how much more > phase shift is needed on the desired frequency to satisfy the > Barkhausen criterion. Of course you have to check that the forward > gain is larger than feedback network losses to have a sustained > oscillation at desired frequency.MMICs are basically Darlingtons. I suppose a Colpitts arrangement should work. Jeroen Belleman
Reply by ●April 28, 20212021-04-28
