The code generates a signal, d, with noise level 1.
The average magnitude of d is 1.
(rnd() returns a ‘random normal deviate’ which is distributed as a normal curve with 0 mean and variance of 1.)
Added to the noise is the signal, cos(2πnt).
We perform the Fast Fourier Transform of the artificial combined signal.
We have chosen a random frequency, n = 60436 but modulated by the constant 1/100.
The signal to noise ratio is thus 1/100.
The peak value in the transform indeed matches the signal that we hid, but with less than a factor of two with the next loudest noise frequency.
The code is parameterized with n = 20.
This is a very large sample size.