Digital Sound & Music: Concepts, Applications, & Science, Chapter 5, last updated 6/25/2013
47
Thus, a 1760 Hz wave sampled at 1000 Hz aliases to 240 Hz (Figure 5.37).
Figure 5.37 1760 kHz wave sampled at 1000 kHz
The graph in Figure 5.38 shows f_obs as a function of f_act for a fixed sampling rate, in
this case 1000 Hz. For a different sampling rate, the graph would still have the same basic
repeated-peak shape, but its peaks would be at different places. The first peak from the left is
located at the Nyquist frequency on the horizontal axis, which is half the sampling rate. After
the first peak, Case 3 is always on the left side of a peak and Case 4 is always on the right.
Figure 5.38 Observed frequency plotted against actual frequency
for a fixed sampling rate of 1000 Hz
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