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Simulator VCO by Cadence


Mar 18, 2024
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How to adjust the RF spectrum oscillation conditions using harmonic balance spectrum and Barkhausen stability criterion to achieve a sinusoidal output signal for High Frequency Voltage Controlled Oscillators.
thank you


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Your oscillator doesn't work, it's obvious.
There is a Component that checks Open Loop Gain and Closed Loop Phase in ADS. But there should be at least equivalent in Cadence ADE. If you are able to refer to ADS Documentation, read about this component.
Home > Component Libraries > Components-Analog RF > Introduction to Circuit Components > Probe Components
You can also create a similar circuit to emulate this component. It will simply give you Nyquist Diagram on a Polar Plane and you will understand about RHP and obviously Oscillation Frequency.
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If you are certain your circuit is designed properly, then use initial conditions to set V1 to low and V2 to high and simulate.

If not, since your oscillator appears to be an LC-tank; make sure your gm-stage is producing enough gm (>1/Rp).
Some oscillators will find a stable DC solution and fail
to start. A "kicker" ipulse / ipwl could be a fairly harmless
simulation crutch. Also look to tolerances, an oscillator
starts on thermal noise (in real life) but in simulation a
too-crude transient tolerance can "soak up " that energy
with no circuit result.

If you kick it and it still doesn't start then there's probably
a design problem in there somewhere.

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