Home▸Engineering & Materials▸Phase-Locked Loop: How Circuits Lock onto a Signal's Frequency

🔁 Phase-Locked Loop: How Circuits Lock onto a Signal's Frequency

Interactive 3D PLL block diagram where introducing frequency and phase offsets in a reference signal shows the voltage-controlled oscillator adjusting until it locks in phase and frequency.

Engineering & Materials3DAdvanced60 FPS

A 3D block diagram of a phase-locked loop — reference oscillator, phase detector, loop filter and voltage-controlled oscillator — where detuning the reference in frequency or phase shows the feedback loop pulling the VCO back into lock.

🔬 What It Demonstrates

The phase detector measures the angular gap between the reference and VCO spinner markers; the loop filter integrates that error into a control voltage; the VCO's spin rate follows the voltage until the phase error collapses to a steady offset — the definition of "locked."

🎮 How to Use

Detune the reference frequency or jump its phase and watch the loop re-acquire lock. Widen the loop filter bandwidth for faster but noisier tracking, or add reference noise to see the filter's smoothing at work. Use the kick button for a step-response transient.

💡 Did You Know?

Modern chips can pack dozens of PLLs on one die, each synthesizing a different clock rate from a single master crystal reference — the same lock-and-track principle shown here, just at gigahertz speeds.

⚙ Under the hood

Interactive 3D PLL block diagram where introducing frequency and phase offsets in a reference signal shows the voltage-controlled oscillator adjusting until it locks in phase and frequency.

phase-locked-looppllfrequency-lockingsignal-processingoscillatorsengineering

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install