Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

New answers tagged

0

First of all, I think it'd be good to include your result vs the result given by the mentioned library. Here is the code of scipy's ifft. In the docs it states that the function returns a complex array contains y(0), y(1),..., y(n-1) where y(j) = (x * exp(2*pi*sqrt(-1)*j*np.arange(n)/n)).mean(). I suspect that you're trying to write the imaginary ...


5

I think there are a couple things going on here. First, the flatness of your baseline plot is a little deceiving because the tones that you have added (1 - 500 Hz) are all almost exact multiples of the fundamental frequency of the fft (fs/nfft = 1.024 Hz/bin). If you increased nfft by a factor of 10, for example, the finer frequency resolution of the zero-...


7

Since this is a constant spectrogram, you could just as well have just averaged the |FFT|² and plotted that! (The most colorful way of visualizing things isn't always the optimal one; your signal doesn't change over time, so you don't need the time axis of the spectrogram at all.) Quite possibly, in that "easier" representation, you would have spotted this: ...


0

This is a rather late response, but I just came over this question. So if it could of any help to future problems for anyone, I will post an answer: Although your question is pretty comprehensive; In my experience with the Lanczos filter, it is a rather versitale filter especially when it comes to image processing. I have mainly used it for scaling images, ...


Top 50 recent answers are included