Peter Perez wrote:
>
>
> Dear Python users,
>
> I am trying to use a piece of coding for FFT filtering, but I haven't
> figure out how to implement the definitions. The Python tutorials
> mention something about it, but it is not working for me. The piece
> of code that I want to use is posted below. Now, I am interested in
> using the function defined as filter (def filter). It seemed to me,
> that something like this should work (but it does not):
>
> myFilter = Filter() # This is to call the class.
> y_filtered = myFilter.filter(y_raw) # To filter the raw signal.
>
> Thank you all for your kind attention.
> Best Regards, Peter

You've defined the filter() function to take two arguments yet you only
pass one. That would cause a problem.

If that's not what you mean by "not working", please provide further
details on how the results of running your code deviate from your
expectations.

- khill




>
> ###############################################
> class Filter:
> def set_cutoff(self,cutoff):
> self.cutoff = cutoff
>
> def set_band(self,f1, f2):
> self.f1 = f1
> self.f2 = f2
>
> def filter(self,x,y):
> self.delta = x[1] - x[0]
> self.f_Nyquist = 1.0 / 2.0 / self.delta
> self.N = len(x)
>
> self.fft = fft(y)
>
> self.freqs = array(range(len(self.fft))) / self.delta / len
> (self.fft)
> N = len(self.freqs)
> for i in range(N/2):
> self.freqs[N/2+i] = - self.freqs[N/2-i]
>
> self.calculate_condition()
> for i in range(len(self.freqs)):
> print '%10d %10f %2d' % ( i, self.freqs[i], self.cond[i] )
> self.filtered_fft = self.cond * self.fft
> self.filtered_y = inverse_fft(self.filtered_fft)
>
> return self.filtered_y
>
> def calculate_condition(self):
> pass
> ################################################
>
>