Instead of using sines and cosines, we can expand a signal as a series of sine waves of arbitrary phase. If we specify the magnitude and phase of each sine wave, we can approximate a periodic function just as well as if we use sines and cosines. Sines and cosines of the same frequency differ only by a phase shift, and any combination of two such waves can be expressed as a single cosine wave of appropriate phase and magnitude. Click the Sine, Cosine, and Phase Shift buttons to see this. Click the Mag/Phase View checkbox to toggle between the two representations.
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