Questions tagged [window]
The window tag has no usage guidance.
90
questions
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0answers
4 views
Apply window taper for selected window or to full data block in algebraic problem with known frequencies?
First, I'd like to introduce a problem. I try to solve a set of linear equations in LS (Least Squares) sense, i.e. Ax=y (LS) => A^TA x = A^T y.
x is a vector I'm looking for, but y is a measured ...
4
votes
3answers
139 views
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 ...
0
votes
2answers
52 views
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 ...
0
votes
0answers
55 views
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 ...
0
votes
1answer
27 views
minimal signal window size (length)
In order to detect a frequency component of 1 Hz with a DFT - do I need a signal window (signal in time domain) of at least 1 second length (in order to have at least 1 cycle of the desired minimal ...
0
votes
2answers
101 views
why is the signal divided into epochs in EEG classification?
I'm new in EEG signal classification.
Studying the literature on this topic, I wonder why the EEG signals are divided in epochs, so, instead of classifying the whole signal all at once, we usually ...
0
votes
0answers
26 views
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 ...
0
votes
1answer
60 views
Discrete Signal Windowing
How do we apply windowing of 50% (4 samples) to a discrete signal with the odd number of values as 1234567?
Is it done as: ...
1
vote
2answers
406 views
Find the Equivalent Noise Bandwidth
I have already asked (in another thread) how to quantify (specify) the window function I have created. One figure I need it seems is the Equivalent Noise Bandwidth (ENBW) Or Noise Equivalent Bandwidth....
0
votes
0answers
25 views
How to specify a window?
I have developed my own window function for pre-processing signals prior to a DFT (FFT). How do I measure the performance of the window so that I can specify how good (or bad) it is? Maybe other ...
0
votes
0answers
16 views
Noise and harmonic elements w/in a discrete time signal
So I have a discrete-time signal with around 300 samples. It is part of an environmental science application, so is not-strictly periodic although there clearly are periodic components. I have applied ...
1
vote
2answers
52 views
Frequency Support of Window Functions
All window functions, which go from zero amplitude, up, then back to zero amplitude, are all base-band signals. Why is this? Are all functions that have this behavior always band-band aka low-pass?
0
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0answers
72 views
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
1
vote
1answer
39 views
Is it okay to interpolate between overlapping areas obtained using a sliding window?
I am using a 50x50 pixel sliding window which moves left to right every pixel so that it covers a whole binary image which is about 2000x2000 pixels. In the window, the ratio value of black to white ...
1
vote
1answer
77 views
Why coherence function calculation needs averaging of different segments of the signal?
I am trying to understand coherence function calculation. I am working with a non-linear system without any noise. Coherence function is defined as:
I understand that coherence is 1 for N=1, but I ...
0
votes
1answer
111 views
RMS from calculation from PSD using Welch's method [duplicate]
I've used Welche's method on a vibration signal to get the averaged FFT which I want to used to calculate the PSD from which I can calculate the RMS.
Within the Welche method i've use Hann window ...
0
votes
0answers
17 views
Scalable gaussian window
I would like to determine fractional fourier transform of scalable gaussian window function
Can I get help on implementing g(t,u) in MATLAB?
0
votes
0answers
41 views
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 (...
1
vote
3answers
150 views
Rectangular vs Hann windowing
I'm trying to create a basic digital signal processing pipeline, to manipulate a WAV file.
Nothing fancy, I'm just looking to apply some filtering.
My first attempt was to divide the input signal to ...
0
votes
1answer
107 views
Energy using Hanning window
I am a newbie in signal processing. I am testing the Hanning window on a signal. Obviously doing this window also means cut some energy of the signal, and when I do the DFT, the 0 frequency is not ...
5
votes
1answer
587 views
Use of Tukey window and its effect on a graph
I am trying to minimise 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....
0
votes
1answer
118 views
When can a windowed cosine be considered band-limited signal?
I have an exam in the following days and i have no clue of what is the response to this question in the exam:
given this signal:
$$g(t) = H\left(t+\frac{T}{3}\right) f(t) - H\left(t-\frac{2T}{...
0
votes
1answer
66 views
Peak to Average Power Ratio of an exponentially increasing signal
I am having an exponentially increasing sinusoidal signal.
After sampling, I am dividing the signal into frames of length 128 and doing windowing operation with a hanning window of length 128. Then ...
0
votes
1answer
82 views
DTFT of window function applied to input signal
$$x[n] = cos(\omega_1n) + cos(\omega_2n)$$
$w[n] = 1/N$ for $0 \leq n < N, 0$ for everything else
Find the DTFT of $y[n]=x[n]w[n]$ expressed by the DTFT of $w[n]$, $W(\omega)$
I was thinking ...
1
vote
2answers
313 views
Multi Resolution STFT for audio
I am looking at trying to achieve a multi resolution STFT analysis on a log sine sweep audio measurement.
I have an impulse, and I would like to perform two different windowed length FFTs on the ...
0
votes
1answer
64 views
0
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2answers
262 views
Half Window Functions and Formulas
I am looking at implementing different window functions in an application I am making. I have found the formulas for all major symmetrical windows, however I would like to implement half windows.
...
2
votes
1answer
71 views
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) ...
0
votes
1answer
190 views
How to deal with overlap in STFT when considering the highest energy among multiple channels
I have a 4 channels audio file. As a pre-processing step, it goes through an STFT with $T$ frames and $M$ frequencies. The output is divided into magnitude and phase per channel, so for $C$ channels, ...
2
votes
1answer
3k views
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?
1
vote
0answers
47 views
Is there a window with both a lower side lobe level and higher side lobe roll of rate than Blackman
Is there a window with both a lower side lobe level and higher side lobe roll of rate than the Blackman window - even if it is poor or useless for some other reason?
1
vote
2answers
163 views
Multiple different length Windows for high resolution realtime FFT
I am looking at trying to achieve a 'realtime' (as quick as possible to acquire, process and present data) FFT application to analyse audio.
I have setup my app to acquire a set of samples, apply a ...
4
votes
4answers
2k views
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 ...
0
votes
0answers
103 views
How to know the time of my window to calculate the STFT with python knowing only the length?
I am trying to implement a work presented in an IEEE paper where they have mentioned that the STFT was performed on the signal measurements to obtain a spectrogram with no overlap window of 3 min :
I ...
0
votes
1answer
32 views
identify equilibrium region after large transient
I am looking at data from a mechanical system under an unsteady load. I'm trying to find the simplest way to identify the portion of the signal once the system reaches its new equilibrium. Here's a ...
2
votes
2answers
153 views
Fundamental misunderstanding of windowing
I believe I have a fundamental misunderstanding of windowing. I thought that windowing is applied to a signal with pointwise multiplication, then some sort of filtering is then done to it (say using ...
1
vote
2answers
983 views
How to design a lowpass filter using Hamming window and sinc function
I have these three equations and have a noisy voice signal. I have to design a low pass filter of length N=1000 using hamming window technique. I have selected its cutoff frequecny 0.25 (normalized).
\...
4
votes
3answers
3k views
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 ...
1
vote
2answers
445 views
Interpolated FIR filter group delay
I'm trying to design a digital low pass filter with a narrow transition band. My sampling rate is 25 kHz, the cut off frequency is 60 Hz & the transition band width is 4 Hz. I'm looking for about ...
1
vote
0answers
240 views
Windowing a signal by using Hanning / Hamming or… zero padding?
My question is about the use of Hanning or Hamming windows versus "square" windows.
In my understanding, I will use a Hanning or Hamming window to limit the spectral leakage. But, on the second hand, ...
1
vote
2answers
546 views
Short length windowed sinc filter
I have a 50-60Hz signal being sampled at a frequency of 25 kHz & I'm trying to filter all frequencies beyond 70 Hz with a reasonable steep transition band (approx 4 Hz) & good attenuation (~40+...
1
vote
1answer
1k views
Gaussian window and standard deviation
I am trying to figure out how to use the matlab gausswin function which constructs a Gaussian window for $N$ samples with a given standard deviation $\sigma$. The function is defined by
...
1
vote
3answers
9k views
Window period(overlap) and FFT
How does changing the window period (i.e the number of points overlap between two frames) affect the FFT results ?
Suppose that a time series signal was converted to frequency domain by FFT with ...
0
votes
1answer
387 views
fft - spectral leakage from noise into target frequency?
I have an acoustic setup. A sender, emitting a clean sine signal. The receiver is far away. In the time domain, the sine is hardly visible because the noise is nearly as big as the signal. In the ...
-1
votes
1answer
359 views
Should I use window or any filtering to average my data?
I have 80 seconds of data and I have to score my data by taking the average or median (or some other method) every 10 seconds. What's the best way to do this ? Should I just use a regular rectangular ...
-1
votes
1answer
149 views
On-Chip DFT Engine vs Software DFT
I'm new to signal processing. I'm trying to build a network analyzer. So far I was only considering getting the output signal through a 16-bit ADC and then do its corresponding windowing and DFT to ...
2
votes
2answers
1k views
Hilbert transform with a sliding window
I have a input voltage signal which has disturbances present in it. I am actually discretizing the input signal into say $1300$ samples and taking Hilbert transform of the signal by taking $N$ samples ...
1
vote
1answer
66 views
Should zero element be considered to calculate mean when smoothing spectrogram by window?
My (mass spectrometry) spectrogram does not measure the intensity constantly. I obtain the spectrogram, for example,
...
1
vote
4answers
608 views
What do I lose when I set overlap rate to a really high value in STFT
If I don't care about computational cost, is there any cons when I put overlap rate really high in STFT?
2
votes
1answer
2k views
How is a signal multiplied with the window functions?
How the input signal get multiplied with the window functions like Hamming, Hanning, Blackman, etc?
I have tried to multiply the input signal of $10\textrm{ MHz}$ sampled at $100\textrm{ MHz}$ using ...
