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14 views

Coherence vs. Magnitude Squared Coherence

currently I am writing my masther thesis. The theory part is about the turbulent wind field generation, where the coherence (not magnitude squared) is used: $$\text{coh}(f) = ...
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0answers
21 views

Spectral Factorization of Magnitude Squared IIR

Taking an IIR: $$ H(z) = \frac {A(z)} {B(z)} = \frac {\sum_{n=0}^{N} a_nz^{-n}} {\sum_{m=0}^{M} a_mz^{-m}} \qquad z=e^{iw} $$ The magnitude squared of the numerator $A(z)$ (the maths of the ...
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1answer
27 views

zero-phasing frequency components while keeping the same magnitude, in Matlab

How is it possible? I was thinking of taking just the real part of the DFT of my signal (isn't that zeroing out phases?) with real(fft(X)) but the magnitudes ...
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2answers
26 views

phase, magnitude, audio file and information

I've been doing some thinking lately. I know that for image files a larger portion of information is contained in the phase of the signal. How does that go for the audio? Does the same hold or is the ...
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3answers
77 views

MATLAB frequency magnitude spectrum

I am using the following code to generate four sine waves using a sampling rate of 8000. ...
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1answer
28 views

Sketching Phase Spectra Using Group Delay and Magnitude Spectra Informations

I have only magnitude spectra and group delay information and I need to sketch phase spectra from this information. For example, group delay is given like this: $\tau_{g}(\omega) = c$ where c is a ...
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2answers
45 views

Averaging Multiple Magnitude Spectra

I'm currently trying to implement some of the methods found in this paper on intelligent equalization - http://www.aes.org/e-lib/browse.cfm?elib=16792 - The first part of the process is to build a ...
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2answers
130 views

How to compute magnitude and phase response from transfer function in Z-domain?

I have a transfer function $$H(z)=\frac{1+1.2z^{-1}+0.8z^{z^-2}}{1-0.9z^{-1}}$$ from which I'm supposed to sketch the magnitude and phase response. I know that you can transform $z=e^{j\omega}$ to get ...
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1answer
55 views

Energy calculation in frequency domain

I was just wondering... The formula I learned to calculate the energy of the signal is expressed in the time domain: $E_x^{\text{time}} = \sum_{n=-\infty}^{\infty} |x[n]|^2 $ Then, what does the ...
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1answer
49 views

sketching magnitude of frequency response of H(z)

I am trying to plot the magnitude of H(z), I got it to factore, and would like to sketch its plot of magnitude. But I am have trouble evaluating the function. $$ H(z)= ...
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0answers
22 views

generation of frequency with magnitude 1

hi i need to generate F=[F0,F1,........Fn-1] wer n=16 such that lFnl=1..... so i understand i need 16 freq samples whose magnitude sums upto 1..... now i need to generate it in matlab...... can anyone ...
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0answers
227 views

fft magnitude scaling

I use the following code to calculate the fft of 1024 samples of a 200 Hz windowed sinusoid (code taken from aurio touch apple example app): ...
0
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1answer
60 views

Interpreting magnitude of DFT results

I'm working on creating a simple program to render spectrograms like this one. In this plot, the X-axis is time, the Y-axis is frequency, and the color represents the magnitude of the DFT at that ...
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2answers
416 views

Magnitude Spectrum, different magnitudes same amplitude

When the following code is written,the resulting magnitude spectrum shows magnitude values represented by two peaks is different even though they have the same amplitude. why is that? a fast reply ...
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3answers
1k views

Adequate representation of frequency domain amplitude/magnitude of FFT of a signal

I'm quite new to the subject and am having fun playing around with the FFT. What I am currently doing is trying to sample an audio signal and display its frequency spectrum at the same time. This ...
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2answers
78 views

how to make fft ignore phase shift when only interested in magnitude

I have a signal that consists of a sine wave, on which I apply a rectangular window and then an FFT. I'm only interested in the magnitude of the sine wave, and I want it to stay the same even if the ...
0
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1answer
114 views

Change of bin magnitude when phase of signal changes when doing FFT?

I am working on an implementation in which I need to apply an FFT to determine which of 4 frequencies are present in a signal. I am doing a 64 point FFT on a buffer which only is partly filled (the ...
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1answer
62 views

Obtaining the magnitude of the frequency response by plugging $e^{jω}$ into the z-domain transform function?

I am reading a text on discrete signal processing, which states that the frequency response of a signal can be obtained by plugging the value $e^{jω}$ into the z-domain transfer function $H(z)$. In ...
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3answers
954 views

Why are magnitudes normalised during synthesis (IDFT), not analysis (DFT)?

In most examples and FFT code that I've seen, the output (frequency magnitudes) of the forward DFT operation is scaled by N -- i.e. instead of giving you the magnitude of each frequency bin, it gives ...
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0answers
97 views

Constant phase for each frequency?

FFT of some signal $x$ has two parts: $|x|$, which is the magnitude spectrum and $arg(x)$, which is the phase spectrum. I want each frequency to have the same phase. Is there a way to accomplish this? ...
1
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1answer
137 views

Plot Magnitude from RBJ Biqaud

Currently I'm working out plotting biquads in a vst/au plugin and have problems with the graphics part. I posted in several forums but haven't got a really useful answer for this case. First, tell ...
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0answers
117 views

IIR: get magnitude and phase from coefficients

i'm trying to plot 1)the magnitude and 2)the phase response of an IIR eq with only its coefficients. i've found somewhere that one can find the magnitude response starting with the transfer function ...
2
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3answers
485 views

recover image by only magnitude of image fourier transform

I have a image and I want calculate fft2 of it, after it I want recover image only by magnitude of it. how can I achieve this work? ...
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1answer
1k views

retrieving original data from phase and magnitude of Fourier transform

I use this snippet of python code to transform data to Fourier phase and magnitude and then retrieving original data. ...
1
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3answers
250 views

Fill matlab “ellip” function through transfer function magnitude response

The matlab "ellip" function can be used to design the unquantised coefficient set. From matlab website: $ [b,a]=ellip(n,Rp,Rs,Wp) , $ n: order of filter Wp: normalized passband edge ...
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1answer
454 views

Gradient of total variation of magnitude of complex function for denoising

Say I have a complex function $f^*$ (e.g. a MRI image) that has a near piece-wise constant magnitude, but a non constant phase. If I have an optimization problem to find $f^*$ and set up an objective ...
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2answers
452 views

Matching an LPC Magnitude Spectrum to FFT Magnitude Spectrum

I'm trying to get an LPC magnitude spectrum to match to an FFT magnitude spectrum. Basically I want the peak height in the LPC Spectrum to match the peak height in the FFT Spectrum. Thanks to ...