Sampling, Reconstruction of Unsampled Signal

Cuthbert Nyack
The original unsampled signal can be recovered from the samples by passing the samples through a low pass filter with a bandwidth of half the sampling frequency. In the applet below, the unsampled signal which is a sine in this case is in gray, samples are in magenta, the response of the filter to the first 5 samples are shown by the sinc functions in orange, yellow, green, cyan and pink, and the sum of the responses is in red. The first parameter "w" is the cutoff frequency of the ideal low pass filter. The applet illustrates the effect of the sampling time and filter bandwidth on the reconstructed signal.