# Questions tagged [window-functions]

In signal processing, a window function is a mathematical function that is zero-valued outside of some chosen interval.

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### How to calculate the power of a discrete signal? / Clarification on PSD estimates

I want to calculate the channel power $P_\mathrm{x}$ of a given discrete and complex signal $x[n]$ (with a length of N) in a given bandwidth $B$. I'm aware, that I could probably apply a sharp ...
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### Auto correlation properties of window functions in pulse compression application

It is known that different window functions perform differently and users pick a window function (in amplitude modulation) based on their application or requirement. I am trying to pick a window ...
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### FIR filter design in matlab using Kaiser window (using 'fir1' and 'designfilt')

Here are the specs for FIR filter using Kaiser window. ...
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### Filter, window function and audio signal: how to link them to each other?

I have a question about the implementation of digital filters in CoreAudio. I'm in big trouble because it is a few weeks I'm trying to understand how to implement them. The basic idea is this: while I ...
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I remember having seen a formula of the form $C=\frac{B}{L}$ that relates a duration $L$(s) of a window to its width $C$(Hz) in the spectrum (defined at -3dB or so). The constant $B$ would be ...
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### Window function on large arays

Hello I'm reading the following document to better understand windowing and how to use it. "Spectrum and spectral density estimation by the Discrete Fourier transform (DFT), including a ...
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### Specifications (N) FIR Low Pass Resamplig, Hamming Window

I'm learning about DSP and I've doubts. The resampling process can be do it with only one filter. $L$: Increment Sample Rate Integer $M$: Decrement Sample Rate Integer $f_S$: Frequency Sampling ...
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### Lost power while using FFT with apodizing mask

Previously I asked this question about FFT artifacts. The solution that is most easily implemented is using an apodizing mask on the original image, tapering the borders to zero making the image left-...
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### Increasing the number of points in the frequency spectrum

I have an image with few pixels in length and height. For this image I calculated the two dimensional Fourier transformation. What I got for the frequency spectrum in one direction was a very ...
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### instantaneous frequency

If my signal is $$f(t)=\exp[i\phi(t)],$$ how do I show that $$\int_{-\infty}^{\infty} {\xi}\left|S_f(u,\xi)\right|^2 d\xi = 2\pi\int_{-\infty}^{\infty} {\phi'(t)}\left|g(t-u)\right|^2 dt,$$ ...
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### Windowing of signal before FFT

I am facing an interesting problem: I have a signal in the time domain. In order to avoid discontinuities at the edges of the signal --- which would lead to artifacts when calculating the FFT --- I ...
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### How to determine number of filters in filter bank based on spectrogram of audio signal?

I want to do an analysis and than synthesis of audio signal, which is audio of vowel 'a', using Matlab. For this I need to use filter bank(array of band-pass filters). I have drawn four different ...
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### Blackman window magnitude attenuation

I am trying to compute the fundamental phasor using sliding window DFT. I have employed a Blackman window in conjunction i.e $$\sum_{k=0}^{L_{DFT}-1}x(k) w(k) e^{-j2\pi k/N}$$ where $x(k)$ is the ...
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### FIR filter design using Kaiser window - passband ripple and stopband attenuation

I have been given the following parameters : lower cutoff frequency = $\pi/3$ lower cutoff freq = $2\pi/3$ beta = 5.6533 M = 51 Now I have to get magnitude and phase response of the filter using ...
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### What is appropriate windowing technique for sine burst excitation?

I had to give sine burst to get good SNR. In above Blue color -> Actuation signal or input. Orange -> Response or output. I did use hanning window for both. The frf real & imaginary plot ...
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### What is the spectrum of generalised periodic signals assuming mainlobe covers the first two harmonics?

I found this statement in the paper here which I have difficulty seeing why is it true. Let $H(\omega)$ represent the Fourier transform of a time-windowing function. Assume the width of the mainlobe ...
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### window function between program and math

I'm newbie on signal processing. I know when we program python with window function. (just signal multiply with window) According to Harris paper I know we change w with different window(blackman). ...
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### Variable Window Size of Blackman FIR filter

I am trying to implement an FIR filter with a Blackman window function. The solution I got for my signal filtering problem is to have different window sizes for certain characteristics of the input ...
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### Reconstructing a signal from multiple filtered copies using overlapping tapered windows

I have an audio signal that I need to process and analyse in blocks. I've now decided to process it using overlapping non-symetric Hanning windows of length M = 9600 and a hopsize of R= M/2. I zero ...
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### Gibbs phenomenon, which window to use?

"Rectangular window" and "Triangular window" have gibbs phenomenon So which window should be used in fir filter design to have minimum or zero gibbs phenomenon
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### Fundamental component estimation

I am dealing with phasor estimation (fundamental component extraction primarily), and i am using sliding window DFT (which happens to be very popular for phasor estimation). Now at nominal frequency (...
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### Smooth signal with Hanning

I have an acceleration record and i want to smooth it's spectrum by using a hanning window with Bandwidth=0.5 Hz. How could i do that? Example in python/matlab will be appreciated!
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### Windowing in frequency domain. how to cut a spectrum using window function in frequency domain?

I have a set of measurement data of a FMCW radar and trying to estimate the system transfer function. In the frequency spectrum, I can see multiple peaks due to the non-linearity that exist in the ...
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### Analysis with Window before FFT

I have two signals $x$ (see below) and $k$ (obtained by giving circular shift of 106.5849 in $x$). Before I take FFT of both ($x$ and $k$) I want to do window analysis on them. Kindly can some one ...
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### hamming window for LPC

I am working on a library for generating LPC for speech synthesis. I am currently using a hamming window for the spectral analysis which goes in 200ms blocks over the signal, and does the a-to-k ...
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### Audio output distorted with any FFT Windowing other than rectangular

For an experiment i have a simple application that takes a quadrature signal from a radio and then does the following: Complex FFT -> Inverse FFT -> Cartesian to Polar -> audio out If I tune the radio ...
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### segmenting an EEG data

I have an EEG labeled data, which is the data that used for training, And I want to segment those data based on the time of EEG signal (Time-based Epoching) as a preprocessing step, based on the ...
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### Relation between Gaussian and Savitsky-Golay kernels

I would like to make a mathematical comparison between two methods in my field. One smooths with a Gaussian filter, and one smooths using a second-order Savitsky-Golay filter. Let's say the window ...
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### BandPass and StopBand FIR filters (Hamming) is not working

I have two groups of 3 frequencies of tone (music), First Group Tones: 39 (77.7817 Hz), 40 (82.4069 Hz) and 41 (87.3070 Hz). Second Group ...
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### Reducing latency due to FFT windowing for a real-time signal

I need to compute the amplitude of a certain frequency band as the input to a PID algorithm. My system looks like this: ...
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### Power Spectrum in dBFs

I'm trying to get the spectrum of my signal in dBFS units. I'm not sure what is the refernce that I should devide by. I computed the power spectrum as follows: 1) FFT normalized to the number of ...
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### MATLAB : How to filter a data signal

I have a data signal (column vector) with N values taken over at specific sample rate (dx) at a fixed frequency. After taking the Fourrier transform of this signal and representing it in the Fourier ...