Heck of a way to run an oscillator?

Started by skeptical engineer in sci.electronics.design8 years ago 44 replies

I was looking at the SAW oscillator circuits at a co. called Epcos, and they just take an op amp with the SAW filter in the feedback loop....

I was looking at the SAW oscillator circuits at a co. called Epcos, and they just take an op amp with the SAW filter in the feedback loop. They explain that the op amp amplifies noise, but preferentially at the filter allowed frequency. 2 components. I love the simplicity, but does this approach have any drawbacks?


GHz oscillator

Started by John Larkin in sci.electronics.design7 months ago 55 replies

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...

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.


I want to build an LO

Started by M. Hamed in sci.electronics.design8 years ago 111 replies

Hello the most knowledgeable electronics group on earth! I am trying to build a few LC oscillators for experimenting with mixers. I do not want...

Hello the most knowledgeable electronics group on earth! I am trying to build a few LC oscillators for experimenting with mixers. I do not want to use Crystals, Frequency Synthesis, DDS, etc. Let's say 2 MHz and 100 MHz. I don't know where to start! I have a few RF books and the treatment of oscillator can be one of the following: 1- Too much theory on the analysis of oscillator circuits,...


Oscillator mathematcal problem

Started by bitrex in sci.electronics.design6 years ago 44 replies

Suppose we have the equation for a damped harmonic oscillator driven by a step input, e.g. x'' + Ax' + x = H(t), where A is the damping...

Suppose we have the equation for a damped harmonic oscillator driven by a step input, e.g. x'' + Ax' + x = H(t), where A is the damping parameter. Now suppose we allow A to be any _continuous_ function of x, i.e. steps, delta functions, and their permutations are disallowed. Is there a way to determine which such function damps the system out in the minimum time, _without_ allowi...


Transistor oscillator.

Started by Ian Field in sci.electronics.design6 years ago 56 replies

Is there a rock bottom oscillator that will free run at the frequency limit of whatever transistor is put in it? I was thinking of the common...

Is there a rock bottom oscillator that will free run at the frequency limit of whatever transistor is put in it? I was thinking of the common base job with a capacitor strapped from collector to emitter, but am unsure what to use as a collector load. Basically for testing how good are a collection of vintage germanium transistors. Thanks for any help.


dual gate mosfet oscillator

Started by bitrex in sci.electronics.design8 years ago 22 replies

Anyone have any experience with how dual gate mosfets perform in a crystal oscillator role, at low voltages ( < 3 v), at frequencies say 200...

Anyone have any experience with how dual gate mosfets perform in a crystal oscillator role, at low voltages ( < 3 v), at frequencies say 200 - 500 MHz? -- ----Android NewsGroup Reader---- http://www.piaohong.tk/newsgroup


PIC32 oscillator question

Started by Randy Day in sci.electronics.design8 years ago 8 replies

I'm using the following code to test my oscillator configuration setup, and I'm puzzled. No matter what values I use for fpllidiv, fpllodiv,...

I'm using the following code to test my oscillator configuration setup, and I'm puzzled. No matter what values I use for fpllidiv, fpllodiv, fpllmul, etc., my PORTB scope waveform never changes its period. Code runs fine on the device, I just expect to see the output vary with clock freq settings. I must be missing something obvious. Any suggestions? /* MPLAB v8.92, if that's ...


The HP Original for sale

Started by bitrex in sci.electronics.design4 years ago 33 replies

HP 200C Wein Bridge oscillator up for sale on eBay. $125. "Thank You For Looking At Are Item"

HP 200C Wein Bridge oscillator up for sale on eBay. $125. "Thank You For Looking At Are Item"


oscillator for driving a transformer

Started by panfilero in sci.electronics.design9 years ago 12 replies

Hello, I'd like to drive a small high frequency transformer at around 100kHz-300kH= z with a 24Vpk signal, I tried building up an astable...

Hello, I'd like to drive a small high frequency transformer at around 100kHz-300kH= z with a 24Vpk signal, I tried building up an astable multivibrator with a = couple of caps and transistors but i couldn't get it to drive the transform= er, it wouldn't even make anything close to a nice square wave.... anyone k= now of a better simple oscillator circuit I could use to do this? thanks! ...


Spice Simulation, I Know Nothing

Started by Anonymous in sci.electronics.design3 years ago 13 replies

Just put up a simple oscillator to learn how to do simulations and I can't get it to work. I mean I know the oscillator will work but I can't even...

Just put up a simple oscillator to learn how to do simulations and I can't get it to work. I mean I know the oscillator will work but I can't even begin to make this thing simulate. I am clueless about the commands, even the dialog boxes. Start time, stop time, all that. I just want to run it. I can't even find the probe. The help files didn't reveal much. I looked online about t


it oscillates!

Started by Anonymous in sci.electronics.design2 years ago 54 replies

During this shutdown, I did a little pcb layout for my triggered common-collector Colpitts oscillator, and had some boards fabbed....

During this shutdown, I did a little pcb layout for my triggered common-collector Colpitts oscillator, and had some boards fabbed. A manufacturing person came in today and built a couple for me. It's a triggered 125 MHz oscillator that will be used to time delays in a laser system. We want minimal time jitter so I tried to keep the Q up. The inductor is a Coilcraft Midi-Spring. I used ...


Relaxation oscillators and SPICE

Started by Piotr Wyderski in sci.electronics.design7 years ago 25 replies

I am unable to simulate the followingg PUT-based relaxation oscillator in the most recent LTspice (with BC547B and...

I am unable to simulate the followingg PUT-based relaxation oscillator in the most recent LTspice (with BC547B and BC557B): https://upload.wikimedia.org/wikipedia/commons/9/9f/PUT_LED_blinker.png Nothing wants to oscillate. Looking for a bug I have also tried the simplest possible neon lamp oscillator (with Vstrike=100V, Vhold=50V, R=220k, C=1u), but there are no scillations either: ...


LTSpice simulator of my oscillator is far from reality; bad models?

Started by Clifford Heath in sci.electronics.design8 years ago 25 replies

Folk, Thanks to some good help here in the past, I have a nice clean oscillator (for my new fox transmitters), but I'm having trouble with...

Folk, Thanks to some good help here in the past, I have a nice clean oscillator (for my new fox transmitters), but I'm having trouble with the LTSpice simulation at higher frequencies. I'm assuming that the Intersil Spice model for the CA3046 is bad, and I know JT has a better one. Anyhow, I have two questions about the attached LTSpice schematic. 1) When I set it to 30MHz, LTSpice ...


Amplitude-dependence of 1/f noise

Started by Phil Hobbs in sci.electronics.design6 years ago 11 replies

I was reading a paper by Rubiola & Brendel on oscillator noise, and he made the interesting comment that since 1/f noise is multiplicative in...

I was reading a paper by Rubiola & Brendel on oscillator noise, and he made the interesting comment that since 1/f noise is multiplicative in nature (e.g. conductance fluctuations in thick-film resistors), whereas other noise sources are additive, the 1/f noise corner of an oscillator depends on the amplitude. He also says that circuit simulators all get this completely wrong, because...


Transformer/excitation coil for Armstrong oscillator

Started by Anonymous in sci.electronics.design3 years ago 11 replies

Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to...

Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to be with designing the transformer and/or excitation coil. Are there any good tutorials or related material online. Any hints/ suggestions would be of immense help. Thanks in advance.


Help With Royer Oscillator

Started by Kooner in sci.electronics.design11 years ago 19 replies

Hello, I have a working Royer Oscillator. This version is not current fed. It is a push push tolpolgy and the LC oscillationis are set by...

Hello, I have a working Royer Oscillator. This version is not current fed. It is a push push tolpolgy and the LC oscillationis are set by the transformer inductance and winding capacitance. The schematic looks like a multivibrator except the reistors in the collectors are replaced withthe half primaries of the pushpull transformer. This circuit has BJTs and has a sine wave output but I w...


So what makes this buzzing-radio sound anyway?

Started by Tim Williams in sci.electronics.design8 years ago 18 replies

www.seventransistorlabs.com/QRZ.mp3 (...QRN? I don't remember the Q-codes.) Recorded from a Theremin-in-progress, but the same sound shows up...

www.seventransistorlabs.com/QRZ.mp3 (...QRN? I don't remember the Q-codes.) Recorded from a Theremin-in-progress, but the same sound shows up all over the airwaves, LW, SW, professional receivers or homemade. In this case, it shows up when connecting only a foot of wire to a 5MHz oscillator (yes, rather high for a Theremin, this is for S&G's at the moment). Said oscillator seems to ...


transmission line Colpitts oscillator

Started by John Larkin in sci.electronics.design3 years ago 12 replies

I've been thinking about this https://www.dropbox.com/s/yuu737wb3cqizph/TX_Line_Osc_3.JPG?dl=0 as a roughly 500 MHz clock oscillator for...

I've been thinking about this https://www.dropbox.com/s/yuu737wb3cqizph/TX_Line_Osc_3.JPG?dl=0 as a roughly 500 MHz clock oscillator for some digital stuff. My FPGA guys claim they can accept that as an LVDS clock input. The comparator would be LVDS in and out, FAN1101 maybe, if it is really fast enough. So I have a question for some more RF-ey guys than me. Q1 furnishes negative r...


Hartley Oscillator: Two Coils, No Cap

Started by Kevin Foster in sci.electronics.design5 years ago 17 replies

Would it be possible to build a single transistor Hartley oscillator by substituting a pancake (spiral) coil for each leg of the center-tapped...

Would it be possible to build a single transistor Hartley oscillator by substituting a pancake (spiral) coil for each leg of the center-tapped inductor, and then placing one coil flat on top of the other so the insulation between them takes the place of the cap? If the current in each coil is made to flow opposite to the other, could their proximity to each other also be used to vary th...


A Brief Review of RF Oscillators in LTspice

Started by Steve Wilson in sci.electronics.design3 years ago 11 replies

Some people struggle to try to get an oscillator running in LTspice. This article describes different types of Colpitts and Clap oscillators snd...

Some people struggle to try to get an oscillator running in LTspice. This article describes different types of Colpitts and Clap oscillators snd shows how to calculate the component values to get them to run. Crystal oscillators are discussed, along with a method to drastically shorten the startup and settling time in order to view the actual oscillator waveforms. The descriptions are a...