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14 views

Simulate noise on the x axis for raw time-of-flight mass spectrometry signals

I am analyzing raw mass spectra produced by a time-of-flight mass spectrometer. These spectra are 2 dimensional signals that consist in intensity values with respect to mass/charge values. Here is an ...
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0answers
21 views

A question related to “quadrature carrier multiplexing” [migrated]

While studying 'Qaudrature carrier multiplexing', I came across these statements in my text material: "Precisely varying the phase of a high-frequency carrier sine wave in a hardware circuit ...
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1answer
95 views

Compare phase and magnitude spectrum results of 2 Images [duplicate]

I have read that from Fourier transform we obtain magnitude and phase spectrum. The magnitude spectrum tells you how strong are the harmonics in a image and the phase spectrum tells where this ...
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1answer
101 views

What is the right way to extract particular frequency phase information from FFT?

Signals acquisition: Two proximity sensors are positioned Orthogonal to each other. These would be measuring the vibrations of a rotating shaft. Problem: Each of these 2 signals has two dominant ...
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1answer
69 views

FFT of signal with starting value zeros

I have a signal, ...
2
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1answer
100 views

How to find phase values on precise pixel locations of a given Image? [closed]

I have computed magnitude and phase spectrum of cameraman Gray scale image using fft function. Here, we get magnitude and phase spectrum of the whole image. .Please see the reconstruction of image ...
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0answers
45 views

DTFT of beat signal with shift due to multiplication

I am simulating a FMCW radar (Ramp signal is used for transmission)and I have created the transmit signal from matlab FMCW model ...
2
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0answers
27 views

Signal conjugation detected on RF recording samples, why?

I collected spread spectrum signals at 400 MHz at low elevation angles using Software Defined Radio complex sampling over the seasons. I noticed that over watery, icy surfaces, the RF samples are ...
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2answers
61 views

recovering phase of sine signal from FFT

I have a simple sine function as $sin(2\pi ft + \phi)$. I want to obtain the phase signal $\phi$. I tried to use FFT to calculate $\phi$. In matlab I do the following ...
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2answers
175 views

Can anybody explain about phase shift and phase spectrum terms in case of multidimensional signal?

I know about phase of a 1D signal. But when I go into higher dimensions like 2D,3D etc, it becomes headache to grasp the concept. What are the terms phase shift and phase spectrum mean in case of ...
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1answer
43 views

How to translate “phase” into “delay”

Suppose that a system induces a phase of -90 degree, how do I practically measure the delay in the signal coming out of the system? I think time lag would be a more useful measure than phase. ...
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2answers
30 views

Phase spectrum range

I computed spectrum analysis of sine wave (without windowing and zero-padding) and I got plots as follows: As far as I know they are correct. When I learnt about DSP, I got the huge problem with ...
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0answers
13 views

Beam profiler for detecting phase shift?

I'm new to signal processing and currently looking to detect a phase shift in a 633nm 10mW HeNe laser that is being run through a Michelson interferometer. Is a CCD beam profiler capable of detecting ...
0
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1answer
29 views

2 points and instantaneous phase sufficient to estimate amplitude and frequency of sinusoid?

If you have 2 points (x1y1,x2y2) in a Cartesian grid, there are an infinite amount of sinusoids that pass through them. But if you are also given the instantaneous phase (Th0) in radians or degrees at ...
0
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1answer
58 views

Fragmented recovered image using a Phase Retrieval Algorithm named Error-Reduction

After reading the paper Phase retrieval algorithms: a comparison by J.R.Fienup. I implemented the Error-Reduction Algorithm in MATLAB. The initial phase input was randomly generated, so the final ...
0
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1answer
110 views

matlab fft phase response square wave

I am new to phase analysis, recently I have been trying compare the phase between the input signal and output signal of a system. From the code below, I simulated a square wave and plotted the phase, ...
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2answers
80 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 ...
1
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1answer
70 views

Manual Extraction of Filter Phase Response with MATLAB using sweep sine

I'm currently at a loss for why my code seems to not be working. I'm doing a sine sweep on a filter to calculate its freq and phase response. The frequency response checks out, however the phase ...
0
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1answer
41 views

Phase is not linear in frequency domain after delay in time domain

When impulse response is symmetric around sample zero phase entirely zero. in = 0 , 0 , 0 , 0 , 1 , 1 , 1 , 1 , 0 , 0 , 0 -> This gives zero phase result As I know if I apply a delay in time ...
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2answers
70 views

Phase response of FFT in practice

As I know if the impulse response is symmetric around sample zero phase response should be entirely zero. The code below just set a rectangular window for vector "in" ...
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0answers
22 views

Amplitudes and phases of transform of an image

I have recorded an image of a large macromolecule and after several types of image analysis, have obtained a rotationally averaged image, that is not quite perfect, but appears to show 6-fold ...
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2answers
51 views

Deconvolve a symmetric sequence into minimum-phase and maximum-phase sequences

I learned in school that any real-valued, even-symmetric sequence can be expressed as the convolution of a minimum-phase sequence and its time-reverse, which is maximum-phase. In my case, the ...
1
vote
1answer
168 views

Phase difference between two sinuisoidal signal

Currently, I have two signals, the main components of both signals are 60Hz, but both also have weaker response at 180Hz + small amount of noise. As shown in the photo below, I want to find the phase ...
0
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3answers
103 views

In filter design, why isn't it possible to have a frequency response with phase 0?

A linear phase filter will cause a delay in the output signal of the filter. If I'm not mistaken, a filter with phase equal 0 would cause no delays in the output signal. Can someone explain me why ...
0
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1answer
49 views

retrieve phase of an extrapolated periodic 1D signal

I have a periodic signal on a given grid, say (in matlab format): ...
0
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1answer
53 views

Phase Estimation in speech enhancement

I am reading a recent paper titled "Phase Estimation of Speech Enhancement - unimportant, important, or impossible?" by Grekmann et al. published in the 2012 the IEEE convention. The paper proposes an ...
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0answers
132 views

Image processing: Importance of phase

I was doing some experiment on image processing. I wanted to explore the importance of phase and Magnitude. I followed the following approach: Take 2 image of same dimension. Apply Fourier ...
0
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2answers
134 views

Tutorial for a stereo Phaser in C++?

I was searching for a tutorial on how to implement a stereo Phaser in C++. All i´ve found was sourcecode with little or no explanations which did´nt help me much. Does anyone know a Tutorial with ...
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1answer
66 views

Help me understanding this source code of a Phaser

I tried to understand the following source code of a Phaser: ...
1
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2answers
121 views

3 Band Crossover with Linkwitz Riley Filter

I would like to write a 3 Band "EQ" with BiQuad Filters but for some reason, I get some phase distortion. The problem already got discussed here. I found out that I need to work with Allpass filters ...
1
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1answer
71 views

the phase spectrum of a zero-phase wavelet is not zero!

I am going to plot the phase spectrum of a zero-phase ricker wavelet. I calculate the fft of the wavelet and use the phase or ...
0
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0answers
71 views

For discrete signals, why does phase change not correspond to time shift?

I'm going through a Signal Processing lecture where the professor mentions this fact and the argument given is: Suppose you have a sinusoidal signal: $Acos(\omega t)$ Now if you change the phase of ...
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0answers
26 views

calculate signal power for windowed sine like signal while ignoring phase shift

What is the best way to calculate the signal power of a sine like signal, recorded into a small buffer (32 samples), in such a way that phase shifts of a few samples will not have an influence on the ...
1
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2answers
79 views

Validating cross corrolation between sine and cos, shouldn't pahse lag be pi/2?

I am trying to use cross correlation instead of FFT to find lags between 2 signals. I am trying to understand cross correlation by using it on sin and cos and expecting phase lag to be pi/2 but it is ...
0
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1answer
118 views

How to find phase difference between 2 signals, one has an unknown function

I have a system that is forced by a sinusoidal function with specific amplitude, phase and frequency ( all these are known ahead of time). I get a deformation of sinusoidal form as well (think of a ...
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0answers
34 views

Phase difference betwen 2 signals, 1 signal with unknown function

I understand this question may have been addressed however I have a major difference. I started out with a sinusoid of form A*sin(2 pi freq t + phase) and I know ...
0
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0answers
10 views

Is there a 3-dimensional correlate to phase residues?

In 2D phase unwrapping problems, the presence of a "phase residue" indicates that the answer obtained from a path-following unwrapping algorithm is dependent upon the path taken. A phase residue is a ...
0
votes
1answer
56 views

Instantaneous phase calculation problems

I am currently struggling with a problem when calculating the instantaneous phase of a wavefield using a 1D Hilbert transformation. The scheme is as follows. 1D Hilbert transformation of wave field ...
0
votes
1answer
46 views

Phase angle operator, Implemention and drawbacks

Let assume we have a signal as: $\color{blue} {x(t)=M e^{(-\beta.t)} e^{j(\sigma .t+\delta )}}$ By applying phase angle operator we have: $\color{blue} {Phase[x(t)]=Phase[M e^{-\beta.t} e^{j(\sigma ...
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0answers
21 views

Testing whether instantaneous phase algorithm works 2D

I need to calculate the instantaneous phase $\phi$ of a 2D wave field $U$ in C which can be derived by one of two 1D Hilbert transforms $H$: $$ q(x,z) = H_1[U(x,z)] = 1/\pi \int_R U(x-\zeta,z) ...
0
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1answer
76 views

How to calculate the time delay of a signal by a first-order filter

lets assume following signal $$x=a_1 \sin(2\pi f_1 t) + a_2 \sin(2\pi f_2 t).$$ This is passed through a simple single-pole filter with cut-off frequency $f_c$. How is $x$ delayed by the filter (peak ...
3
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2answers
271 views

Using Goertzel Algorithm in under-sampling

I plan to calculate a signal's phase using Goertzel Algorithm. I have 2 signals coming to microcontroller's ADC. Need to measure the phase difference between them. Signals are 15MHz sinusoids. Sample ...
2
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0answers
128 views

Convolving two complex signals - relationship between phase

Suppose two continuous complex domain signals are convolved, how is the magnitude and phase of the resultant signal related to the magnitudes and phase of the original signals?
-1
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1answer
196 views

once again,confusion between phase and group delay [duplicate]

Despite,reading up on this I'm unable to find crystal clear clarity on the differences b/w phase and grpdelay functions and interpretation of grpdelay's output. I have designed a low pass butterworth ...
1
vote
1answer
44 views

How are phase values able to capture motion from video?

I know that the phase spectrum contains most of the structural information about the image importance of phase. But I want to know more about importance of phase spectrum related to video signals. I ...
1
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0answers
35 views

Remove phase mis-alighnment in digital signals

Apologies for the poorly formulated question -- I've been away from DSP for a while. Let us say I have amplitude vs time data for N signals. where amplitude is -127 to 127. For each signal I have say ...
1
vote
2answers
183 views

Compensate for phase shift of Hilbert transform

I'm using Octave and trying to use the "instfreq" function from the time frequency toolbox which requires an analytic signal input. To get this analytic signal I'm using the Octave function "hilbert" ...
1
vote
1answer
59 views

Is phase and amplitude information necessarily lost when undersampling?

Is phase and amplitude information necessarily lost when undersampling if you have a constant periodic single frequency sinusoidal? My second question is: How can one determine the undersampling ...
0
votes
1answer
84 views

Phase reference of a periodic signal

Assume an arbitrary (discrete) signal that is periodic and known over a whole period. I need a way to select a characteristic point along the signal such that I can always retrieve it even when the ...
2
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0answers
106 views

Doppler shift using PLL

I am trying to apply phase lock loop to calculate phase shift due to doppler effect and finally calculate the doppler frequency($\Delta f$). I am assuming that the received wave is of the form, $r(t) ...