采样与混叠

Keeping points, losing the rest

The cosine trap

The ambiguity is fundamental

Aliasing turns structure backwards

The samples of a fast cosine happen to fit a slower cosine exactly. Why does every standard reconstruction method return the slow one?

A car's wheels appear to spin slowly backward in a video, and a reporter's striped tie flickers into new patterns. What single mechanism explains both?

A wave has frequency $w = 2\pi K/N$ with $K = 3$ cycles per window and $N = 12$ samples per window. Write the period in samples.