File:Hall2006 Sampling uncert.png

Summary
Measuring a single frequency. (a) Three 64 ms signals sampled at 1000 Hz with a frequency sample spacing of 1/0.064 = 15.6 Hz. The signals are 43 Hz (blue), 47 Hz (red), and 51 Hz (green) sine waves, with Hann windows applied. (b) The spectra are very similar, and would be unlikely to be discriminated, especially in the presence of noise.