Questions tagged [window]
91 questions
10
votes
3 answers
Moving average vs. Moving median
I have read in many places that Moving median is a bit better than Moving average for some applications, because it is less sensitive to outliers.
I wanted to test this assertion on real data, but I am unable to see this effect (green: median, red:…
Basj
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7
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Proof that the rectangular window has the best resolution
The resolution of a window is typically defined by the width of its spectral mainlobe (3dB-width or null-to-null width). It is often stated that the rectangular window has the best resolution among all windows. In my work, I'd be looking for a…
Lukas
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6
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4 answers
What is Frequency Resolution?
Im trying to tackle the following problem while still not having a firm idea on what "frequency resolution" means :
Suppose we sample a continuous time signal with sampling period Ts = 1/2000, and then use a window of length 1000 on the resulting…
Αποστολης Καρασμανογλου
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5
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3 answers
Can I use more than one Window on an FFT?
I was wondering if it is possible to take a signal and run it through an FFT multiple times with a range of different windows, and then combine/average the results to get a more accurate Signal analysis than just one window. For example, could i run…
Jacob wood
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4
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3 answers
Correct method for processing FFT in realtime
I am attempting to build a 'live' FFT for continuous analysis of an audio signal. I am relatively new to this, but have attempted the full thing, and then updating the graph at 20Hz refresh rate. My FFT is working with regards to identifying the…
Sam Proctor
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4
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3 answers
Understanding overlapping in STFT
I understand the concept of the STFT. In order to avoid spectral leakage, you use a Hann window that overlaps by 50%. However, the problem that I have, is that the example code online does not account for this.
What I mean is, if the signal is…
John Menoso
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4
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1 answer
Inverse the Hanning Window
I am using the following formula to calculate the Hann values for a set of points:
$$
w(n)=0.5\left(1-\cos\left(2\pi \frac nN\right)\right)
$$
To implement this in java, I am using the following code:
private static void applyHannWindow(final…
angryip
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4
votes
2 answers
Why is each window/frame overlapping?
I am currently reading up on some speech recognition theory.
As it speech signals usually are non stationary, but if a speech is seen in a very small time frame can it be deemed stationary, as would only consist of the sound of phoneme.
As…
Bob Burt
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4
votes
1 answer
What is the LOW frequency resolution rule analogous to Nyquist?
If I'm analyzing a signal in the frequency domain, I know about the well known Nyquist criteria that the sample frequency must be > 2x of the highest component present in the signal.
However, there are very few references related to the lowest…
Paul S
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3
votes
1 answer
Hanning and Hamming Window
I am new in the field of signal processing. What's the different between Hamming and Hanning window? When we use the former and latter?
Andreas Chandra
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3
votes
2 answers
Zero padding - High amplitude
I have a set of 512 samples that I have collected with a sensor. I'd like to apply zero padding to it, for better frequency bin resolution. However, all the tutorials I see to make this occur center around the idea that your wave is localized around…
angryip
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2
votes
1 answer
Window with optimal sidelobes for a given ENBW / frequency-resolution
Is there a family of windows which is "optimal" in terms of energy above/below a boundary, but with controllable ENBW/bandwidth? By optimal, I mean maximising energy concentration inside some bandwidth $B$ like:
$$\frac{\int_{-B/2}^{B/2}…
cloudfeet
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2
votes
1 answer
Biorthogonal Windows
I am starting to study about the concept of biorthogonal windows and the relation to (Discrete) Fourier transform and short-time Fourier transform (STFT).
I have not found an introductionary review of the concept and Google search mostly refers to…
Triceratops
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2
votes
1 answer
Use of Tukey window and its effect on a graph
I am trying to minimize the noise in a spectrum of a variable. I am trying to to divide the time history in equal parts, to do the FFT of this time history parts and to do an average between these FFT.
Doing this procedure I have find that the…
Ashish Bhigah
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2
votes
1 answer
What is the proper way to filter out unwanted noise from accelerometers?
I'm a beginner in signal processing and have a hard time to filter out environmental noise from the floor vibration data collected using accelerometers.
I have tried using butterworth filter (IIR) and sinc function (FIR) along with some window…
DrakeL
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