Currently I work on my Masterthesis which deals with structural dynamic simulation. As a part of it I have to filter a Signal with a FIR-Filter. From that Filter I know the Frequency Response (picture).
The code is written in Python and I'm not sure how to apply the IFFT since I have just a real input.
Thank you for your answer robert bristow-johnson!
In python there is function called irfft which stands for inverse real fft. So a ifft for real input. But it seems that something goes wrong with the time signal. I'm aware of that I have no phase in this case. But I guess for Filters in Signal processing it is pretty common to just have the frequency response and calculate the impulse response out of it? So there should be a right way to do it... Unfortunately I'm no expert in Signal processing and at the moment I'm pretty much stuck at this problem.
UPDATE: I think the correct way is to add just zero phase (so +0j) to the frequency response. For the ifft the first bin has to be 0 valued, from 1 - N/2 i add my frequencies as I have it from the response, and from N/2 - N I add the conjugate complex numbers (as the phase is zero the values are just in descending order). Hope this will do the trick.