Sinusoids, Noise, & Their Spectrum
by Mike Martin
Consider a sum of three sinusoids and another term that represents noise (actually random numbers drawn from a restricted interval):
The user inputs values for the parameters A1, A2, A3, A4, ω1, ω2, ω3, and N. Note that N is the number of sample points of the sinusoidal signal. Also the noise (or random variable) is drawn from uniform distribution within the interval [-1/2, 1/2]; the variable V represents this noise. It may be of interest to examine the spectrum of the sinusoidal signal when there is no noise -- set A4 = 0. The first graph is that of the signal and the second graph is that of the Fouler spectrum.
Enter in the values of the parameters, then press the "Visualize" button.