Signals · interactive lab
Sampling Lab
The dots are all a digital system gets. Change how often you sample a wave and watch a different frequency pass through exactly the same dots.
One second of signal
Cyan: original wave. Dots: measured samples. Dashed amber: a baseband wave with the same samples.
Reconstruct from measurements
Samples outside this one-second window are assumed zero. Boundary ringing and finite-window error are expected; this is not ideal infinite reconstruction.
n = 0 · t = 0.0000 s · measured = 0.0000 · alias = 0.0000
Different waves, identical samples
Your 9 Hz wave looks like a 3 Hz wave to this sampler. The original oscillates between measurements, where the sampler cannot see it.
Read the numbers
- Nyquist frequency
- 6 Hz
- Baseband frequency
- 3 Hz
- Samples per cycle
- 1.33
The dashed curve is an analytically constructed alias, not an interpolation of this finite window. Negative signed frequencies reverse the sine's direction to keep its phase consistent.
Ideal, noise-free sampling of a single sine wave. All calculations run locally.