# Questions tagged [stft]

Short-Time Fourier Transform

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### Definition of an adaptive threshold for signal detection

Good day. I would like to try to create a signal detection algorithm based on STFT. I am interested in the implementation of an adaptive detection threshold that will be determined per bin (by ...
949 views

### Cochleagram vs STFT for CNN-based speech segregation

I’m working on a project (python-based) that would use ideal ratio masks (IRMs) as a basis for cleaning noisy speech in various environments. Specifically, this will be accomplished through the use of ...
114 views

### Unwindowed STFT of sine, closed form solution and insights (sliding FFT)

I seek to calculate, mathematically, the unwindowed Short-Time Fourier Transform of $$\cos(2\pi f t + \phi)$$ i.e. any arbitrary real-valued sine: any frequency, duration, phase shift, and number of ...
124 views

### Interpolation of STFT between time and frequency bins

I am trying to identify and remove airplanes in a time series obtained at a radio meteor receiver. Here we have a spectrogram which displays the power content of my signal as a function of frequency ...
254 views

### Why does NMF (Non Negative Matrix Factorization) decompose a spectrogram into time and frequency component?

I compute the NMF over a spectrogram (magnitude of STFT of a signal) in this way: W,H = NMF(MyStft,r) # where r=2 is the rank W and H respectively contain the ...
68 views

### writing from STFT to audio using ISTFT adding harmonics to audio not present before

I'm doing quite a bit of the samething as I wrote in this post here : Shifting frequency peaks such that w[i] moves to w[i/n] using STFT and IFFT I'll quote from it here to present the issue I now ...
43 views

### Shifting frequency peaks such that w[i] moves to w[i/n] using STFT and IFFT

I am trying to do a kind of frequency compression on say 20 most energetic frequencies in a particular slice of a STFT. If w[i] is the frequency peak for a slice of STFT at a particular time, then I ...
2k views

### Hop size in STFT

I am reading the documentation of scipy.signal.stft function. My question: is the 'noverlap' parameter of this function equivalent with STFT hop size?
12 views

### Calculating PSNR using STFT of sampled signal

I have a baseband IQ sampled signal from a Pluto SDR with a bandwidth B and also fs = B, how can I calculate its PSNR using the STFT of the signal in Matlab. Do I need to take into account the RBW of ...
1 vote
74 views

### Window Type Effect on Pwelch vs ShortTimeFFT PSD Result?

I am trying to make sure I understand the output scaling of pwelch. I am using the PWelch function to compute the PSD of a signal and I have manually computed the PSD from an STFT output. The results ...
1 vote
415 views

### How to plot the STFT of a .wav file in GNU Octave?

I'm quite new to signal processing and am trying to find the short time fourier transform of an audio sample and plot it (I believe the best way is as a spectogram?) using Octave (similar to this ...
142 views

### what does librosa.stft do that makes it different?

My understanding of the Short Time Fourier Transform is that first I need to frame the signal and window it, after that apply an fft on these windowed frames. Using Librosa: ...
1 vote
86 views

### Advantage and Disadvantage using Mel Spectrograms over STFT in speech/waveform synthesis

I want to ask you a question about the waveform synthesis or more spesifically speech synthesis. Most of the state-of-the art papers use mel-spectrograms as their inputs, because it mimics the human ...
1 vote
86 views

### STFT normalization

In Scipy's implementation of STFT, an argument allows to scale the result as a spectrum or as a psd : ...
1k views

### Is "Windowed Fourier Transform" a synonym for "STFT"?

Sometimes I find the notation WFT (Windowed Fourier Transform) while other times I see STFT (Short Time Fourier Transform). Are they the same?
137 views

### Why not overlap save for inverse stft

Since STFT uses overlapped sections of the input signals and compute DFT, it resembles overlap-save method used for block convolution, instead the overlap-add method for block convolution uses non-...
79 views

### Comparing results for spectrum generating in matlab using STFT and Filterbank approach

To analyse data in the frequency domain I often use functions like stft() in Matlab. Inspired by this video and this article I have compared the results of ...
947 views

### How to calculate short-time fourier transform (STFT) when the window length is greater or smaller than the FFT size?

I have been trying to understand the weighted overlap-add (WOLA) method. By searching papers and posts in dsp.SE, I found that the window length can be larger and smaller than the FFT size. 1. Window ...
1 vote
137 views

### reproduce Scipy's stft

I failed to reproduce Scipy's stft. When I have tried to remove all the possible modifications and go the minimal example, I converge to the following: ...
1 vote
249 views

### How to implement STFT for processing audio [closed]

I should start this off by saying I’m a hobbyist and by no means a student. I’ve been reading “The Audio Programming Book”, and attempting to implement STFT on the stm32 based Daisy platform. In order ...
350 views

### What is the difference between STFT and Gabor filter?

My understanding is that a Gabor filter gives us information about when in the input signal does the frequency of interest (equal to the frequency of the sinusoid in the Gabor Filter) occur, thus ...
1 vote
321 views

### Overall spectrum computation from Short-Time-Fourier-Transform

I am trying to computing the overall spectrum of a given signal from its Short-Time-Fourier-Transform. I am using python to do this and I wrote my function to compute the STFT: ...
802 views