Questions tagged [phase]

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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
199 views

Phase Modulation and Intermodulation Anomaly ? (Spectrum plots inside - **Updated**)

I have a MATLAB script for modelling a two tone signal (a sum of two sinusoids) going through a non linear transfer function (such as an amplifier). The amplitude of a signal is amplified non linearly,...
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2answers
108 views

Frequency response of a microphone using a sine sweep

I want to determine the frequency response (magnitude, phase) of a microphone. I have another "good" reference microphone whose frequency response I know. I understand that I can use a good speaker ...
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0answers
44 views

Phase noise definition

I have some problem with understanding the phase noise definition formula. please see this image: I can't understand the paragraph that I show ? near it. How is it possible to get phase noise > 0 ...
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0answers
56 views

Gapped-signals.. How to stitch?

Dear signal processing enthusiasts: I am forced to cut off a part of a multi-frequency signal, creating a "gap" as shown in the figure. (only one frequency to simplify illustration). If I inject ...
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0answers
154 views

How to design all-pass filter by specifying phase requirements?

I want to delay the part of signal above (or below) specified frequency, but I don't find any books or tutorials to tell how to design is. The commonly used biquad APFs (such as the one introduced in ...
2
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0answers
96 views

Calculating Phase Response for 2 microphones given the input

I want to measure and compare the phase response of two identical microphones. To do this, I have a pressure chamber, which allows to apply the same pressure to both microphones. I apply a sweeped ...
2
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0answers
250 views

Amplitude/phase recovery on noisy signal

I have a noisy signal that has an ac component of fixed frequency but variable amplitude and phase. I'd like to recover the ac component. The signal (blue trace) is mostly smooth, but has a few ...
2
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0answers
44 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 ...
2
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0answers
741 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?
2
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0answers
91 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 ...
2
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0answers
481 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) =...
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0answers
2k views

Phase of an image in the frequency domain

The following picture is amplitude and phase of an image filtered using Gabor filter in the frequency domain. I'm trying to reproduce the results, I'm getting valid results for the amplitude I think, ...
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0answers
485 views

How to find the phase lag between a sinusoidal input force and the response?

I have a system that is forced by a sinusoidal function with specific amplitude, phase and frequency. I get a deformation of sinusoidal form as well, and I would like to find the phase lag. I use FFT ...
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0answers
25 views

how to reconstruct an phase information from the magnitude spectrogram

I need to recreate the phase of a spectogram of magnitude and when inverse fourier, that the sound is understandable and not pure noise Observe these softwares https://photosounder.com/ http://...
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0answers
33 views

Does phase margin exists only for linear systems?

If possible, how to determine the phase margin for nonlinear systems?
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1answer
37 views

Measuring group delay through a linear phase filter

I'm having a difficult time wrapping my head around a phase/ group delay problem and it corresponding to where you start sampling so I built up a system to test some of these issues. The system passes ...
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0answers
34 views

When plotting the cosines of the phases of some sensors, I got an interesting plot

I have a laser that I modulate at some frequency, typically 1250 Hz. I have a sensor that tracks what happens inside a reactor when it's illuminated. I am doing Fourier analysis on both the laser ...
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21 views

Calculate phase lag between two signals with perturbed frequencies

This type of question has been asked quite a few times on this forum and others now, but I still haven't found a satisfactory answer to my problem. Given an input signal: $$x_1(t)=\cos\big(2\pi ft\...
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0answers
27 views

When do phases not exist for spectrograms?

I have been reading a paper on the "Single pass spectrogram inversion" and I came across this in the Introduction part. In many applications, the analysis and modification of the Short-Time ...
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1answer
43 views

How to achieve a smoothed frequency phase response with no outliers

I have two sampled signals, which I then perform wavelet analysis on, by synthesising the Filterbank, perform the dft on each kernel, and the dft on the sampled signals, and multiply together. ...
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0answers
25 views

How does phase relate to motions in an image?

There is lots of research based on exaggerating motions by decomposing an image into complex sub-bands using pyramid representations such as the complex steerable pyramid and manipulating phase ...
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0answers
114 views

How does a Costas Loop lock to one of multiple BPSK signals

I've been looking into how GPS receivers work in terms of signal processing. When a GPS receiver tracks the received signal, it often uses a Costas loop to synchronize the carrier. How that works ...
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0answers
73 views

Can Reassigned-STFT be an invertible transform? Algorithm for “Signal => Reassigned-STFT => masking => Reassigned-ISTFT => Output signal”

It is well known in DSP that this is a successful method to modify audio signals: Signal => STFT => masking => ISTFT => Output signal For example, ...
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0answers
784 views

Simulating Phase Noise: How to do it?

I have a system that I am simulating, and I want to add phase noise to the process. I didn't know how to do it, so I have been conducting an literature review. I found a good reference with an "easy ...
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0answers
30 views

How does the M-law Synchronizer work?

Relatively new to DSP, I've came across the approach for phase-estimation of PSK-Signals x(k): My question is: What do we get by exponentiating the Baseband-Signal?
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1answer
122 views

How can you 'perfectly' reconstruct phase for transients in a modified audio absolute spectrogram?

I am currently working on the absolute spectrogram of an input audio signal. I am using non-negative matrix factorization to separate out the rhythmic components (bass drum, snare drum and hi-hat) of ...
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0answers
149 views

How to get the phase offset from the instantaneous phase

The phase components of a signal that they are got from the Fourier Transform, are simply, the phase offset of each sinusiod. Which is the $\phi$ in equation $1$. However, in case of Hilbert transform,...
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0answers
29 views

How do I smooth-over transition from a time-series generated by one system to a time-series generated by another system?

So I have generated a time-series with length on 2N samples, where the first N are generated by one auto-regressive system and the N+1 to 2N are generated by another, similar, auto-regressive system. ...
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0answers
582 views

Hilbert Transform, filters - two different phase graphs

Relationship between magnitude response and phase response for minimum phase is: Phase plots are obtained from Hilbert transform of real magnitude values. Input to Hilbert transform was a vector (...
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0answers
171 views

Importance of phase of time-series for PSD

I have $m$ complex-valued time-series $z_m(t_n)$, which I am currently analyzing. I started by calculating their PSDs and CSDs. These exhibit an unexpected peak at a given frequency, which is present ...
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0answers
155 views

Derive Maximum of zero phase rotated wavelet from rotated wavelet

I have one question concerning phase rotation of signals and I am not sure wether it works or not: Let's assume we have a zero-phase wavelet x(t) i.e. Ricker wavelet. Unfortunately, in our ...
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0answers
96 views

transmitting data using phase modulation of two sine waves passed through distortion

I have two sine signals with frequencies f1 and f2, and phase p1 and p2. I modulate the phase of these signals to transmit two symbols simultaneously, chosen from the set [0,1,2,3]. For example, I ...
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0answers
123 views

Calculate a Kind of Equivalent Baseband Signal by Examining the Zero Crossing

I have a device (whose behaviour I can't change) which does the following signal processing: The incomming signal contains two frequencies $f_1$ and $f_2$. One has a huge amplitude, the other a ...
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0answers
530 views

Estimating The Time-delay using the Phase of the Cross- Correlation function

I am relatively new to time delay estimation. I am working on a project where I am estimating the time-delay from the phase of the cross-correlation function (CCF), since it is more reliable in ...
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0answers
20 views

How to correct phase using arctangent as Phase Detector

I have a DPLL that's trying to lock to a DSB-SC input signal with a carrier whose phase is $\theta$. So after some mixing and filtering (Costas Loop), I have these two signals ($\hat{\theta}$ is the ...
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0answers
36 views

How to deal with phase incoherence issues after manipulating a signal in the frequency domain?

Let's say that we want to manipulate a signal in the frequency domain using a short time Fourier transform and once we're done , we use an inverse STFT (plus overlap and save) to convert the results ...
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0answers
16 views

Is it possible to restore audio that has been tonally modified by a phase vocoder?

My objective is to apply some process to the modified audio that allows me to obtain the original audio. I think it can be solved through machine learning techniques. I don't know if there is any ...
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0answers
26 views

Skew measurement with phase deviation

I am calculating the standard deviation of skew (= phase/2*pi*fin) from the 1000 monte carlo runs of the following code. In the y0, there is no input skew., but in y1 there is a skew present. Its ...
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0answers
34 views

Design of low pass filter

I'm designing a low pass filter to identify the DC content of a signal. The most important aspects of my application are the accuracy and the speed of the identification. I would like to know if the ...
0
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1answer
65 views

Manually creating a lowpass filter from the frequency domain: what phase?

In an attempt to gain a better understanding of DSP, I want to create a very simple (1D) lowpass, or I think more correctly "stop-band" or "band-reject" filter, to filter out a single frequency, e.g., ...
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1answer
32 views

Question about quadrature signals

My question is related to this article: https://www.dsprelated.com/showarticle/192.php I think I understand mostly everything until this sentence: "The directions in which the impulses are pointing ...
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0answers
70 views

Implementing Costas loop for 4-PAM

EDIT 2: OK, regarding the code I’ve pasted below, and seeing the FFT plot, I suspect the LPFilters aren’t working since I’m getting $0.5*m(t)*[cos(2 \pi f_c t ( \theta_e)+cos(\theta_e)]$ instead of $0....
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0answers
37 views

Dual FFT - difficulties extracting phase

I am performing dual FFT analysis on a system. 1) I generate a Log Sine Sweep signal and save it as my reference array 2) I then produce an inverse filter to correct for amplitude and save this as ...
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1answer
39 views

Phase measurement with FFT for DMM Keithley 7510

I am currenly working on a measurement driver for the DMM Keithley 7510. I implemented a harmonics measurement using FFT (from MathNet library). First I simply sample my input voltage signal and ...
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0answers
22 views

The mean value of phase noise as a stochastic process

What is the mean value of phase noise as a stochastic process? Where can I get a theoretical analysis of this topic? PS: PLL produces cos(2*πfct+φ(t)). The phase noise refers to φ(t). The mean value ...
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0answers
27 views

Generating a phase modulation frequency spectrum with jitter

I would like to produce a frequency spectrum plot like this: (from All About Circuits) I know that one can take the modulation frequency and multiply it by a given order and scale by the modulation ...
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1answer
46 views

digital phase lead algorithm

I have two sine signals A and B which are simultaneously sampled at 2500 Hz using ADC. Through oscilloscope, I find that signal B lags A by about 5 degrees. I would like to digitally lead signal B to ...
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0answers
116 views

Preamble detection using cross-correlation

I am generating a preamble with a sequence of [1 -1 1 -1 1 -1....] and spread with a barker-11 sequence. Now, the transmitted signal becomes [B(Barker), -B(Inverse of Barker), B, -B,....]. In channel, ...
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40 views

Signal delay in phase interferometry?

I want to write program for phase interferometry to understand how its work. For the beginning I generate signal, which arrives on two antennas with delay. Matlab code: ...