I'm not a terrific oscillator expert, but: your oscillator is squegging. This happens when there are two resonant frequency in your network where there is gain. I suspect that the ratio between C1 and the series combination of C2 & C3 is too extreme.
Trying to build a super-regen receiver? Move the junction of R1-R3 to V1-R2, and lose R3 & C4.
Scott
It looks like the OrCAD SDT I had, except I had II, with no simulator. I used to take these same screencaps, load them into Paint Shop Pro and do a negative image. The background turns white and the red lines turn cyan. Then it was easy to edit 4 or so pallette entries and have proper black-on-white.
Cheers! Rich
Hi all, Please look at the screen grab I made below of a circuit simulation in MultiSim2000. Its a series resonator oscillator hooked up to a scope. The Oscillator takes about 3 mins to start up but I was wondering if the output should look like this. I thought I would generate a clean VHF signal (50Mhz) with a constant amplitude.
Any ideas or thoughts welcome!
Cheers, Kevin.
I read in sci.electronics.design that Xanax wrote (in ) about 'Verify screen grab of my VHF Series Resonator Oscillaor', on Fri, 25 Mar 2005:
What a BEAUTIFUL squeg! I bet you could try a dozen oscillator circuits and not get another as classic as that.
Basically, it's oscillating so hard that one of the active devices (I can't see the schematic clearly - why the black background?) is being biassed off, which cause the oscillation to die away. The bias then collapses and the oscillation starts again.
It may still not work. Try changing R2 to 10 or 100 ohms & put a .1uF at the collector to ground. And put an RF choke or resistor of 1K between the emitter and ground. Then it will look like a typical series-tuned Colpitts or Clap oscillator.
Scott
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