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Signals & Telecommunications

From radio antennas to optical fiber — how information rides physical waves through space and glass. Visualize Fourier decomposition, OFDM subcarriers, signal noise and channel capacity live in your browser.

9+ simulations Three.js · Web Audio API · Canvas 2D Fourier · FFT · OFDM

Category Simulations

Wave phenomena — from mathematics to modern communications

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Popular ★★☆ Moderate
Fourier Series
Any periodic signal is a sum of sinusoids. Drag the amplitude and phase of each harmonic and watch the composite waveform assemble. Build a square wave, sawtooth, or draw your own target shape.
Canvas 2D Fourier Series Harmonics
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★★☆ Moderate
Wave Equation
Interactive 2D wave PDE on a membrane. Click to create pulses, set boundary conditions (fixed / free / absorbing), change wave speed and see interference, reflection and standing modes.
WebGL FDTD Standing Waves
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★☆☆ Beginner
Chladni Patterns
Vibrating plate nodal patterns: sand migrates to where the plate stands still. Tune frequency and plate shape — see the same phenomenon that reveals speaker cone resonances and seismic modes in Earth's crust.
Three.js Standing Waves Resonance
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Double-Slit Experiment
Wave-particle duality in action. Switch between classical wave interference and quantum probability wave collapse. Vary slit width, separation and wavelength — see the diffraction envelope change in real time.
Canvas 2D Interference Diffraction Quantum
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New ★★☆ Moderate
AM / FM Modulation
Watch a message signal ride a carrier wave — amplitude modulation varies envelope depth, frequency modulation swings the carrier frequency. Live sideband spectrum shows Bessel components.
Canvas 2D AM / FM Sidebands Bessel
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★☆☆ Beginner
Doppler Effect
Moving source emits circular wavefronts that bunch together in the direction of motion and spread behind it. Adjust speed and frequency — watch the Mach cone form as the source goes supersonic.
Canvas 2D Waves Mach Cone Acoustics
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New ★★☆ Moderate
Live FFT Spectrum Analyzer
Real-time FFT of test signals (sine, noise, sawtooth, chord). Logarithmic frequency axis, peak hold, dB amplitude, oscilloscope waveform.
Web Audio API FFT Canvas 2D
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★★☆ Moderate
Optical Fiber
Total internal reflection guiding light around bends. Vary core refractive index, cladding ratio and wavelength. Watch modal dispersion broaden short pulses — the trade-off limiting data-rate over long fibers.
Canvas 2D Snell's Law Total Internal Reflection
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New ★★☆ Moderate
Antenna Radiation Patterns
Polar dBi plots for dipole, Yagi-Uda, patch, and phased array. Steer the beam electronically with a phase shift slider.
Canvas 2D Radiation Pattern Phased Array
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New ★★★ Advanced
Digital Filter (FIR/IIR)
Design Butterworth, Chebyshev and windowed-sinc filters interactively. Visualise Bode plot (magnitude + phase) and pole-zero diagram. Apply to a live signal and see real-time frequency response.
Canvas 2D DSP Bode Plot
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New ★★★ Advanced
OFDM & WiFi Subcarriers
Visualise how WiFi splits data across orthogonal subcarriers. Add multipath echoes and see how the cyclic prefix prevents intersymbol interference.
Canvas 2D OFDM WiFi 802.11
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New ★★★ Advanced
Phase-Locked Loop (PLL)
Watch a PLL lock onto a noisy carrier. Adjust VCO gain, loop filter bandwidth and damping ratio — see phase error converge and jitter reduce in real time.
Canvas 2D PLL Clock Recovery

Related Articles

Signal theory tutorials and deep-dives

Guide The Fourier Transform Explained An intuitive walkthrough — from summing sinusoids to the DFT matrix, FFT algorithm and spectral leakage.
Explainer Shannon's Nyquist Theorem Why you need to sample at least twice the highest frequency — and what aliasing looks like when you don't.
Tutorial How OFDM Powers Modern WiFi Subcarrier orthogonality, cyclic prefix and channel estimation — the maths behind 802.11ax.

Explore Other Categories

More simulations across science disciplines

About Signals & Signal Processing Simulations

FFT, filters, sampling, convolution, and frequency analysis — live

Signals and signal-processing simulations make the mathematics of frequency-domain analysis concrete and interactive. Discrete Fourier transform visualisers decompose user-drawn waveforms into sinusoidal components and display amplitude and phase spectra in real time. FIR and IIR filter designers plot magnitude and phase responses from pole-zero configurations in the Z-plane, animating how filter coefficients shape signals passing through them.

Nyquist–Shannon sampling-theorem demos show aliasing artifacts when a signal is sampled below 2f_max and explain why reconstruction requires an anti-aliasing low-pass filter before the ADC. Correlation and convolution animations automate the integrate-and-shift operation that underlies matched filters, autocorrelation measurements, and linear-systems analysis. These tools support signals and systems courses at university level and are used by RF engineers, audio DSP developers, and machine-learning engineers working with time-series data.

Each simulation in this category is built with accuracy and interactivity in mind. The underlying mathematical models are the same ones used in academic research and professional engineering — just made accessible through a web browser. Changing parameters in real time and observing the results is one of the most effective ways to build intuition for complex scientific and engineering concepts.

Key Concepts

Topics and algorithms you'll explore in this category

Fourier TransformTime-to-frequency domain conversion (DFT/FFT)
AM/FM ModulationCarrier, modulation index, and sidebands
OFDMMulti-carrier orthogonality and cyclic prefix
Digital FiltersIIR, FIR, convolution, and frequency response
Shannon LimitChannel capacity C = B·log₂(1 + S/N)
Antenna PatternsRadiation diagrams: dipole, Yagi, phased array

Frequently Asked Questions

Common questions about this simulation category

What signals and communications topics are simulated?
FFT spectrum analysis, AM and FM modulation sidebands, OFDM multi-carrier modulation, digital IIR/FIR filter design, Shannon channel capacity, and antenna radiation pattern visualisation.
How does the FFT spectrum simulation work?
You draw or load a time-domain signal. The DFT is computed via the Cooley-Tukey FFT algorithm and displayed as a magnitude/phase spectrum. You can add noise and watch the spectral lines change.
What is OFDM and can I see it here?
OFDM (Orthogonal Frequency-Division Multiplexing) splits a high-rate stream into many narrow sub-carriers spaced at 1/T intervals (orthogonal). The simulation shows how a multipath channel creates inter-symbol interference and how the cyclic prefix eliminates it.