Home▸Signals & Telecommunications▸Phase-Locked Loop — 2D Mixer, Loop Filter & VCO

Phase-Locked Loop — 2D Mixer, Loop Filter & VCO

2D PLL simulator with a real analog-multiplier phase detector, a genuine RC-style loop filter and a VCO whose frequency actually tracks the filtered error, integrated sample by sample. Watch live waveforms lock and the phase error converge after a reference frequency step.

Signals & Telecommunications2DAdvanced60 FPS📱 Mobile-adapted⇄ 3D version

Details

CategorySignals & Telecommunications

RenderingCanvas 2D

DifficultyAdvanced

Target FPS60

ControlsA step-size slider sets the reference-frequency jump in Hz; +Step and -Step buttons apply it immediately and 'Return to base frequency' undoes it, each showing a real lock-in transient. A loop-bandwidth slider (alpha, 0.002-0.15) sets the one-pole loop filter's response speed, trading faster lock-in against a noisier steady-state control voltage. Play/Pause toggles the simulation and Reset restores all state and history buffers.

phase-locked loopPLLVCOloop filterphase detectormixercontrol theory2d

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This is a genuine 2D control-loop simulation of a phase-locked loop, not an animated diagram. An analog-multiplier phase detector compares the real reference and VCO waveforms every sample, a one-pole low-pass loop filter smooths that mixer output into a control voltage, and the VCO's own frequency shifts in proportion to that voltage before being integrated back into phase — closing the loop exactly like real PLL hardware. Step the reference frequency to see a real lock-in transient, and adjust the loop filter's bandwidth to explore the classic lock-speed-versus-stability tradeoff.

⚙ Under the hood

A genuine 2D phase-locked-loop simulation: an analog-multiplier phase detector compares the real reference and VCO waveforms every sample, a one-pole RC-style loop filter smooths the mixer output into a control voltage, and the VCO's frequency shifts proportionally to that voltage and is integrated back into phase — a real control loop, not an animation. Step the reference frequency to watch a genuine lock-in transient and tune the loop bandwidth to explore the lock-speed-versus-stability tradeoff.

phase-locked loopPLLVCOloop filterphase detectormixercontrol theory2d

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install