Forums

GHz oscillator

Started by John Larkin April 27, 2021
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.

In article <vapg8g56dptb7moktkh53usv391uiq2cde@4ax.com>, 
jlarkin@highland_atwork_technology.com says...
> > 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.
Not a useful answer for you, but back in the 60s I was doing research on tunnel diodes. I was impressed on how, if we were not careful, one plus one two passive components would oscillate at a high (for us, at the time!) frequency. Remarkable for a two terminal device, because of its negative impedance.
On Tue, 27 Apr 2021 23:04:05 +0100, Mike Coon
<gravity@mjcoon.plus.com> wrote:

>In article <vapg8g56dptb7moktkh53usv391uiq2cde@4ax.com>, >jlarkin@highland_atwork_technology.com says... >> >> 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. > >Not a useful answer for you, but back in the 60s I was doing research on >tunnel diodes. I was impressed on how, if we were not careful, one plus >one two passive components would oscillate at a high (for us, at the >time!) frequency. Remarkable for a two terminal device, because of its >negative impedance.
I loved TDs when I was a kid. My college senior paper was "The Tunnel Diode Slideback Sampling Oscilloscope." A few people still make germanium back diodes, but I think TDs are gone. The fab process was insane. TD's were hard to curve trace because they really wanted to oscillate in the negative resistance region. Here's an oscillator with a phemt. I don't really like it because it seems to be tricky in simulation. It can do weird things like go chaotic with some part values. Version 4 SHEET 1 880 680 WIRE 176 -256 0 -256 WIRE 0 -192 0 -256 WIRE 176 -192 176 -256 WIRE -240 -48 -336 -48 WIRE -48 -48 -144 -48 WIRE 0 -48 0 -112 WIRE 0 -48 -48 -48 WIRE 176 -48 176 -112 WIRE -240 -16 -272 -16 WIRE -96 -16 -144 -16 WIRE -272 32 -272 -16 WIRE -96 32 -96 -16 WIRE 0 32 0 -48 WIRE -336 112 -336 -48 WIRE -96 112 -336 112 WIRE -48 112 -96 112 WIRE 0 176 0 128 FLAG 0 176 0 FLAG 176 -48 0 FLAG -272 32 0 FLAG -96 32 0 FLAG -48 -48 D FLAG -96 112 G SYMBOL mesfet -48 32 R0 WINDOW 0 86 29 Left 2 WINDOW 3 61 56 Left 2 SYMATTR InstName Z1 SYMATTR Value SAV551 SYMBOL res -16 -208 R0 WINDOW 0 54 44 Left 2 WINDOW 3 53 73 Left 2 SYMATTR InstName R1 SYMATTR Value 50 SYMBOL voltage 176 -208 R0 WINDOW 0 88 48 Left 2 WINDOW 3 59 93 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value PULSE(0 3.3 1n 1n 0 1) SYMBOL tline -192 -32 R0 WINDOW 0 4 -65 Bottom 2 WINDOW 3 2 -55 Top 2 SYMATTR InstName T1 SYMATTR Value Td=100p Z0=70 TEXT 144 88 Left 2 !.MODEL SAV551 NMF( vto=0.08, Beta=0.3,\n+ Lambda=0.07, Alpha=4 B=0.8, Pb=0.7,\n+ Cgs=0.997E-12, Cgd=0.176E-12, Rd=0.084,\n+ Rs=0.054, Kf=5e-11, Af=2) TEXT 262 34 Left 2 !.tran 0 20n 0 1p TEXT -328 -240 Left 2 ;3 GHz Phemt Oscillator TEXT -280 -200 Left 2 ;JL Apr 27 2021 I might dremel breadboard it, and a MMIC version.
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
On Tue, 27 Apr 2021 16:10:37 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@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! MAX2750 is a 2.5 GHz VCO, but it's Maxim. What ever happened to the Analog Devices acquisition of Maxim?
On Tue, 27 Apr 2021 16:52:22 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

>On Tue, 27 Apr 2021 16:10:37 -0700 (PDT), Lasse Langwadt Christensen ><langwadt@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! > >MAX2750 is a 2.5 GHz VCO, but it's Maxim. > >What ever happened to the Analog Devices acquisition of Maxim?
Being Maxim, of course most of the versions are obsolete.
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 connectors
> > MAX2750 is a 2.5 GHz VCO, but it's Maxim. > > What ever happened to the Analog Devices acquisition of Maxim?
afaiu they are just waiting for EU antitrust approval
On 28/04/2021 05:35, John Larkin wrote:
> 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. >
Any chip or module with wifi or bluetooth. ESP32 or ESP8266 with wifi ought to do, or one of the Nordic ones with bluetooth. I think you need +4dBm for 1Vp-p if my lazy maths is right. You get free power adjustment, modulation, and it is PLL locked to a crystal reference. You also get a free microprocessor included. As to whether it is a sine wave, it must be close, to get FCC approval without fancy filters before the antenna.
On Tue, 27 Apr 2021 12:35:17 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

>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.
This is neat. I wonder if it would actually work. Version 4 SHEET 1 880 680 WIRE 176 -256 0 -256 WIRE 0 -192 0 -256 WIRE 176 -192 176 -256 WIRE -224 -48 -272 -48 WIRE -112 -48 -144 -48 WIRE -48 -48 -112 -48 WIRE 0 -48 0 -112 WIRE 0 -48 -48 -48 WIRE 176 -48 176 -112 WIRE -112 -16 -112 -48 WIRE 0 32 0 -48 WIRE -112 64 -112 48 WIRE -272 112 -272 -48 WIRE -64 112 -272 112 WIRE -48 112 -64 112 WIRE 0 176 0 128 FLAG 0 176 0 FLAG 176 -48 0 FLAG -48 -48 D FLAG -64 112 G FLAG -112 64 0 SYMBOL mesfet -48 32 R0 WINDOW 0 -40 105 Left 2 WINDOW 3 -70 134 Left 2 SYMATTR InstName Z1 SYMATTR Value SAV551 SYMBOL res -16 -208 R0 WINDOW 0 54 44 Left 2 WINDOW 3 55 75 Left 2 SYMATTR InstName R1 SYMATTR Value 50 SYMBOL voltage 176 -208 R0 WINDOW 0 56 36 Left 2 WINDOW 3 47 82 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value PULSE(0 3.3 1n 1n 0 1) SYMBOL ind -240 -32 R270 WINDOW 0 73 57 VTop 2 WINDOW 3 69 60 VBottom 2 SYMATTR InstName L1 SYMATTR Value 3.9n SYMBOL cap -128 -16 R0 WINDOW 0 -60 23 Left 2 WINDOW 3 -67 52 Left 2 SYMATTR InstName C1 SYMATTR Value 1.5p TEXT 40 72 Left 2 !.MODEL SAV551 NMF(vto=0.08, Beta=0.3,\n+ Lambda=0.07, Alpha=4 B=0.8, Pb=0.7,\n+ Cgs=0.997E-12, Cgd=0.176E-12, Rd=0.084,\n+ Rs=0.054, Kf=5e-11, Af=2) TEXT 248 -8 Left 2 !.tran 0 20n 0 100f TEXT -320 -224 Left 2 ;3 GHz Phemt Oscillator #3 TEXT -272 -176 Left 2 ;JL Apr 27 2021 -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
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? :)