The result of the DFT is a complex number. This can be plotted either as a magnitued, as I've done on this web page, or as an angle. The magnitude is the hypotenuse of the triangle formed by the real and imaginary parts of complex number (where the imaginary part is plotted on the y-axis and the real part is plotted on the x-axis). The angle is
angleradians = arctan( imag / real ) angledegrees = (angleradians * 180)/pi
The graphs below show the sine function with various offsets, along with the a plot of the result of the DFT, shown in angles (meansured in degrees). Note that like the magnitude plots, the angle plots are symetric, so only half of the points are shown here.
Ian Kaplan, September 2001
Revised:
Back to A Notebook Compiled While Reading Understanding Digital Signal Processing by Lyons
