Lab · convolution
Sliding convolution
Step across a short signal and inspect the exact sum produced by a three-tap kernel.
Interactive experiment
One output, multiply by multiply
Which input values contribute to one sample of a three-tap smoothing filter?
The fixed kernel is [0.25, 0.5, 0.25]. Mathematical convolution reverses its indexing; this symmetric kernel looks unchanged, a convenience that can hide the distinction from cross-correlation.