Fourier Series

Sum harmonics to approximate periodic signals. Adjust amplitudes of sine/cosine terms and see convergence toward square, sawtooth, or custom shapes.

Who it's for: Signals, acoustics, and advanced math; synthesis vs analysis view.

Key terms

  • Fourier series
  • harmonics
  • superposition
  • periodic function
  • synthesis

How it works

Finite **Fourier sums** approximating periodic targets: **square** (odd sines), **sawtooth**, and **triangle** (odd sines with 1/k²). Raise the term count to see convergence; near jump discontinuities you still see **Gibbs overshoot** (square/saw). The dashed curve is the ideal limit; cyan is the partial sum. Toggle **animate** to slide phase in time.

Key equations

Square: (4/π) Σ sin((2k−1)t)/(2k−1)

Frequently asked questions

Why do sharp corners need many harmonics?
Discontinuities or sharp bends require high-frequency content to approximate; smooth waves need fewer terms for a good fit.