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This can be accomplished with an analytic time-frequency representation, like CWT or STFT. Goal must be known precisely to attain desired result, however, as time and frequency are coupled and targeting amplitude alone may yield distortion. The steps are: Transform to time-frequency Zero undesired amplitudes Invert Below I generate linearly amplitude-...

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Both are basically convolution of a signal by one or several IIR or FIR filters (a bank of complex filters), that can be implemented in the Fourier domain. However, the "several filters" of the STFT are design together to possess certain "invertibility properties". They cannot be "any bunch of bandpass filters". For instance, ...

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Using an STFT usually implies a set of FFTs or DFTs, each of which is identical to a bank of fixed length FIR filters (depending on any window(s) applied), that FIR filter length being the size of each STFT. If you use a separate pre-filter, you can use an IIR or much longer FIR filter kernel, which may provide better filter characteristics (stop band ...

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STFT is also bandpassing. The method the quote refers to is likely the Continuous Wavelet Transform. The fundamental difference is, STFT uses fixed-resolution kernels spaced linearly, while CWT uses varied-resolution kernels spaced logarithmically. Example CWT filterbank in frequency domain (source; x axis from 0 to pi radians): An STFT with Gaussian window ...

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Your signal has a massive DC bias so your output is dominated by the step response of the band pass filter. It will eventually get there but it's going to take a really long time. Initialize your state with zi = -26040*sosfilt_zi(). See my answer to your other question today. EDIT On second thought: while you can fix some of this in software, you probably ...

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That's actually rather simple. A little bit of trial and error will do the trick. The standard specifies upper and lower limit for the transfer function of the filter. So you can just try a normal Butterworth bandpass and see what happens. The picture below shows a 3rd octave design at 1kHz and a sample rate of 48 kHz. A 2nd order bandpass isn't quite a good ...

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