What is aliasing, and what decides the bandwidth and the sampling rate of a recording? · Lobeworks/17

Aliasing is a fast signal sampled too slowly posing as a slow one, like the wheel of a filmed car turning backwards.

What is aliasing, and what decides the bandwidth and the sampling rate of a recording?

Aliasing is a fast signal sampled too slowly posing as a slow one, like the wheel of a filmed car turning backwards. To avoid it the sampling rate must exceed twice the bandwidth, fs>2Bf_s > 2Bfs​>2B, and an analog filter removes what lies above fs/2f_s/2fs​/2 before the converter. The bandwidth is decided by the physics of the signal (a spike of a millisecond reaches about 10 kHz) and enforced by the filter; the rate is then chosen above 2B2B2B and below what power, data and the link allow.