Linked Questions

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1answer
178 views

iZotope RX's FFT processing?

How does iZotope RX handle the FFT (i.e. how does it manage to perform those processes in the frequency domain without creating glitches) since its able to e.g. Apply another DSP process (even time-...
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1answer
164 views

Advantage of using nonideal filter in purely digital application [duplicate]

Say I'd like to bandpass filter a signal with corner frequencies 1 kHz and 2 kHz (i.e., passes signals between 1 kHz and 2 kHz and suppresses other frequencies) using software like MATLAB. Intuition ...
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1answer
2k views

Simple FFT filtering vs. e.g. butterworth filtering

I am currently working on functional connectivity analysis of EEG, and need to bandpass filter my data into different frequency bands (Delta, Theta, Alpha and Beta). An important thing is that the ...
1
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0answers
51 views

My X ray images have black background, which turn gray after low-pass filter. How to recover blackness?

I am applying a low-pass filter to X ray images, which changes the pixel distribution such that the background goes from black to gray. In the attached figure, this amounts to the mode increasing from ...
1
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0answers
251 views

Zero STFT bins (and not FFT bins)

Filtering by taking FFT, zeroing bins, and inverse FFT is a bad idea, as discussed here. But what about: take a STFT, (i.e. multiply the input signal by moving window function, and take FFT) zero ...
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0answers
32 views

How can I generate an ideal 2D low-pass filter in MATLAB?

I've been tasked with creating a 32 x 32 half-band low-pass image filter in MATLAB. My thinking is to generate the ideal filter mask in the frequency domain and compute the corresponding convolution ...
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0answers
56 views

FFTW audio artifacts when modifying magnitudes in frequency domain

I'm currently working with FFT (FFTW3) that I'm using to apply treatments on audio files frequencies. The Forward/Backward test is passed, since I can get the exact same soundfile when processing ...
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0answers
30 views

Use Cases of FFT in Signal Processing [duplicate]

I am trying to learn about signal processing and fft's applications within it. My understanding is that a classical use case for fft is to remove "noise" (ex. high frequencies that are not supposed to ...
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0answers
52 views

FIR Filter Magnitude Response

This is the shape of the bipolar amplitude function for a FIR filter with odd m: I have 2 questions : If i want to use this FIR as a low pass filter between 0 and $\frac{F_{c}}{2}$ , how can i set ...
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0answers
29 views

Is it possible to recover the time-domain signal after manipulating it in the frequency-domain? [duplicate]

I've worked a fair amount with EEG signals, though I've never had formal training in signal processing, so please excuse my ignorance. The problem is this: my signal has noise at many, many ...
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0answers
106 views

Where to start in the design of my filter to remove 50 Hz

pick any 3 random files from this database, : https://physionet.org/pn3/ecgiddb/ They are subject to 50 Hz powerline interference. We wish to convert from time domain to frequency domain and remove ...
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0answers
33 views

FIR filter window method [duplicate]

In the window method for filter design it is explained that we do an ideal filter and then we pass it to time domain, but it will be time limited and then... Why don't we filter directly in the ...
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0answers
88 views

How enhance amplitude of audio signal without distortion?

After FFT I've set to zero some frequencies and I'd like to enhance the amplitude in order to recover the leak. I'd like to do a normalization in order to avoid distortion. I've done in this way but ...
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0answers
666 views

How to implement a time-varying filter?

I'm working on a 10-second sound, sampled at 44.1 khz. I want to do filtering, and have a desired EQ (equalization) curve that varies over time, as suggested here (here $f0=250\ Hz$) How to ...
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0answers
147 views

ITU-R 2k filter implementation

How to generate the coefficients of an itu-r 2k filter when all I know is my 0 dB point is at 2 kHz and my maximum of 6 dB is at 7 kHz

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