Questions tagged [phase]

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How to estimate Range, Doppler and Angle with FMCW MIMO Radar?

I am trying to obtain the range, Doppler and angle of arrival estimation with an TDM MIMO FMCW radar. Actually, I have completed this process. In doing so, however, a few things remained unclear. ...
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Different complex pairs giving same magnitude and phase

I am trying to fit data of magnitude and phase to get complex pairs(for FFT), but I think it would be a wrong approach as different pairs of complex numbers can give same amplitude and phase , is my ...
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Phase of an FFT after zeropadding

How does zero padding effect phase of an FFT? I thought that symmetric zero padding in the center of an image or signal produces no phase change in the FFT (See Here), but I am getting different ...
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Examples & Applications of Quadratic Phase Coupling

Quadratic phase coupling is defined as follows: Consider the signal $$ x(t) = A_{1} \cos(\omega_{1}t+ \phi_{1}) + > A_{2}\cos(\omega_{2}t + \phi_{2}) $$ which is passed through the quadratic ...
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Slope of phase function

Would appreciate some help understanding if I take the phase function of some transfer function and derivative it in the linear part of it which is around the resonant frequency what does this slope ...
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Autocorrelation & Cross-Correlation -> Main uses in DSP??

Please help understanding the DSP usage of Autocorrelation & Cross-correlation It seems this is strongly linked to calculating phase offsets, frequency offset for carrier recovery, symbol timing ...
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How to estimate the delay in time domain when knowing the phase shift in frequency domain

I am strugling with how to compute the exact value of delay in time-doamin when knowing phase shift in frequency domain. I have a analog circuit, I sweeped about 30 single tones frequency ranging from ...
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1 vote
1 answer
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How to get the time domain of a pulse after an amplitude mask or a phase mask has been applied?

I am a chemist, and I am studying ultrafast spectroscopy. In these spectrscopies, usually a short (femtosecond) pulse of light is used to probe chemical reactions. Now, one of the topics in our ...
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How do we determine the required sampling rate of a closed loop control system?

Consider the controlled dynamical system $\dot{x}_t = f(x_t, u(t-\tau_{sd}))$, where $0<\tau_{sd}$ denotes the time delay caused by sampling. It is intuitively clear that the time delay caused by ...
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2 answers
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Finding phase shift using complex exponential

Suppose I have a sine wave $u(t) = \sin(2\pi f t + \phi)$ of known frequency but unknown phase shift and I want to find the phase shift. One way of doing this is multiply-and-adding $u(t)$ by a $\cos(...
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Phase extraction from Fourier transform

Is it possible in principle to correctly extract the phase from Fourier transform? I just tried to do so using Python, here some attempts: ...
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4 answers
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When concatenating sine waves, how do I phase shift in order to prevent "pops" caused by sudden jumps in amplitude?

I'm writing a synthesizer using numpy and python. I've run into a problem where concatenating sine waves causes 'pops' or 'clicks' when they are outputted to audio, say, via ...
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How do I plot a phase spectrum of rectangular pulse with Matlab?

As you can see, I made a code about rectangular pulse like this. And, I plotted complex-exponential-coefficient and Magnitude-Spectrum-of-Complex-Exponential-Form, Phase-Spectrum of-Complex-...
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3 votes
3 answers
154 views

Using spectogram to speed up a signal - Time Scaling/Phase Vocoder

Background About half a year ago, while learning about spectograms as part of an Image Processing course I took, I was told you can speed up audio using spectograms as follows: Calculate the ...
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2 answers
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why need de-correlated signal for measuring phase noise in laser

when measuring phase noise from a laser by using heterodyne method , we will get the output signal as de-correlated. why we using de-correlated output for phase noise mesurement. how it is related to ...
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Deriving the probability distribution function of the cross-spectral phase

I came across a research paper (\ref{Ref 1}) where the probability distribution of the phase of the cross-spectrum was derived. Unfortunately, I could not understand how the authors arrived at the ...
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Difference between MSK and CPSK

I'm trying to understand the differences between the MSK and CPSK transmission, but I am not understanding some things about it. I understood that they are two signals without discontinuity, but what ...
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Confusion understanding Fourier series line spectra?

I am reading book signals and systems Laboratory with MATLAB where I am studing chapter 5, Fourier series and i trying to understand magnitude spectrum and phase spectrum but i have certain confuisons ...
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Phase of PM signal

Given two signals: s1 is a baseband frequency modulated signal (output of a frequency modulator, FM) and s2 is a baseband phase ...
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1 vote
1 answer
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Problems with PSS phase offset calculation algorithm

I'm trying to implement a carrier frequency offset (CFO) estimation algorithm to correct my phase offset with the correlated PSS signal. The algorithm for a corelated signal y(n) is as follows: y(n) ...
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1 answer
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Accounting for phase shift in time-dependent signals

Background: I am using a vibration sensor and arduino to record signals and log them with timestamps, where the signals need to be time accurate so that I can glean information about which frequencies ...
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1 vote
1 answer
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getting a smoother real-time frequency estimate using the phase for a triangle wave

I'm using a phototransistor and an optical chopper to measure the angular velocity of a wheel, much like how mechanical mice used to work. The signal looks like a triangle wave with some noise in it, ...
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2 votes
1 answer
110 views

My summed sin waves seems to only work if my wavelength is divisible with the time steps. A problem with phase likely

I have created a program in python that can create any generic signal and a time range to display it as shown by the red '--' line below. I then created a way to calculate the phase, amplitude, and ...
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1 answer
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Why can't quantum phase noise in radio astronomy amplifiers just be filtered out after down conversion, instead of down-converting first?

In the related Astronomy SE questions below and their answers, it has become apparent that radio telescope arrays down convert their highest frequency bands before the first stage of amplification. ...
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2 votes
1 answer
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Computing Phase Response: do we reform equations to the form $e^{j\phi(\omega)} C(e^{j\omega})$?

I want to understand how we derive the Phase Response. The general formula is $H(e^{j\omega})=|H(e^{j\omega})|e^{j\phi(\omega)}$ Came across an example where: $H(e^{j\omega})=2\cos(\omega)e^{-j\omega}$...
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3 votes
1 answer
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Best method to measure phase difference between acoustic recordings of sine wave?

I am using multiple digital MEMS microphones in an array which are 8mm apart. Now I recorded a sine wave of 20kHz for calibration (at angle 0°) and want to measure the phase difference over time ...
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5 votes
2 answers
285 views

Group delay compensation for non coincident drivers

Suppose I have a two-way speakers system which can be modeled as a two-way Linkwitz-Riley crossovers network with impulse responses $h_{lp}(n)$ and $h_{hp}(n)$. I would like to equalize the group ...
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1 vote
1 answer
62 views

Resolution of phase measurement using cross Correlation

The setup is the following: I am using a RedPitaya board to measure the phase shift of two input signals. These input signals will sweep logarithmically from 1kHz to 100 kHz in 10 seconds. Currently, ...
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1 vote
1 answer
56 views

Hilbert transform modifications for a non-sinusoidal waveform

I have recently been using the Hilbert transform a fair bit and its ability to return a instantaneous phase and magnitude estimate but it has got me thinking about the meaning of phase. From my ...
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1 vote
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Obtaining the phase component of an integer shift using phase only correlation

I'm trying to implement a sub-pixel estimation approach for my stereo matching project that I'm working on, by using the proposed method in the following paper "Sub-pixel Shift Estimation of ...
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Generate complex signal with sinusoidal phase

I would like to syntethically generate a range of complex numbers whose phase (argument) over t will form a clean sine wave of frequency ...
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1 answer
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Drawing phase of frequency response with phase $e^{j\frac{\pi}{2}}$

Cheers, I have a response function of: $$H(\omega) = \begin{cases} \frac{1}{2}j\omega, |\omega| < \omega_c \\ 0, \text{elsewhere}\end{cases},$$ and I am asked to find draw its magnitude and phase. ...
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0 votes
1 answer
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Phase of AM Signal After Mixer

Let's assume we have a carrier at $f_{c}$, and a message at $f_{m}$ ($f_{c} \gg f_{m}$). Amplitude modulation is used to modulate the message on the carrier. Let's call the modulated carrier $\text{rf}...
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5 votes
1 answer
114 views

Getting phase response from magnitude. How to develop and solve this Hilbert transform?

I'm trying to generate phase data from magnitude data in a frequency function, assuming the system is minimum phase. Using Hilbert Transform. For instance, having this simple system: $G(s) = s$ $G(j\...
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0 votes
1 answer
47 views

Reset signal phase when 2 pi is reached

I am given the distance from the source of radiation of the harmonic oscillation to the point of observation $R$ and signal frequency $f$. I need to find the phase shift due to this distance. When ...
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12 votes
4 answers
3k views

Fastest way to compute Arctan2 on an FPGA

Rip Van Winkle here -- is the fastest and least-footprint way to compute an arctan on an FPGA still to use CORDIC? Or is there a way to leverage block RAM and DSP blocks to speed and/or reduce the ...
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1 vote
1 answer
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Phase noise and frequency noise relationship

I want to know how calculate the frequency noise from phase noise. More clearly calculation of frequency noise spectral density from phase noise spectral density. Please explain deeply how the ...
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1 vote
1 answer
83 views

Differences between MATLAB and WolframAlpha and AstromMurray (minimun phase)

I have the following problem when I graph the phase of my transfer function in matlab I get that it starts at 360 while with wolfram it gives me 0 and if I do the calculation that is in astromurray it ...
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0 votes
0 answers
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Calculating PLV on frequency-domain?

I need to calculate Phase Locking Value of an EEG signal. My data is in frequency domain, it was transformed with Short-time Fourier transform. The formula for PLV is: I see it is a function of time ...
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1 vote
0 answers
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How to use a boxcar averager in conjunction with lock-in amplifier

Suppose there exists a temporal voltage signal composed of short pulses, modulated by a sinusoidal envelope. One desires a hardware-based signal processing scheme to maximize signal to noise ratio (...
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2 votes
1 answer
79 views

BPSK consecutive same symbols

I have a question regarding BPSK. If we want to modulate the bit stream $[0, 0]$ with $T_\text{ bit}=0.25 \text{ sec}$ and the carrier frequency of the cosine that carries the BPSK signal is $2\ \rm ...
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How does phase spectrum compensation works?

I'm trying to find some information that explains how phase spectrum compensation of non-stationary signals methods works, but I can't find an exact description of the procedure. I can't understand ...
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0 votes
1 answer
45 views

Phase difference of two time series

Consider we have two time series and for each of them , we know the phase (Phase1 and Phase2). We want to compute phase difference between these two time series. We define the phase difference as (...
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0 answers
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Recovering phase of harmonics in an arbitrary pulse train

I want to recover the phase of the harmonic components of a pulse train. There's a lot of cool resources out there that talk about recovering power spectra from signals in several ideal and non-ideal ...
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0 votes
1 answer
83 views

How to plot the phase response of Hilbert transform

The time domain signal of Hilbert transform is: $$ h(t)=1/(\pi t) $$ Its frequency response is: $$ H(j\omega)=-j~\text{sign}(\omega) $$ So if I plot the phase according to the equation I obtain: ...
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1 vote
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How to quantify a deterministic system?

So let me layout my question and the thought process on solving it. Say, we have some system, and we want to see how deterministic the system is. By that I mean, I mean if I put some signal (real ...
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2 votes
1 answer
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Combination of type I FIR linear-phase systems

Let $h_1[n]$ and $h_2[n]$ be impulse responses of type I FIR linear-phase systems with lengths $M$ and $N$. What can be said about the phase response of the following filters? $h_3[n] = h_1[n] + h_2[...
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Computing Phase Difference Between Two Channels from SDR

I'm trying to compute the phase difference between two channels of a software-defined radio. I'm providing code for two different methods that I'm trying below. In both cases, I'm transmitting a pure ...
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0 votes
1 answer
121 views

Phasor diagram of Phase modulated signal

While studying the phasor diagrams of Amplitude modulation and Frequency modulation, I am stuck at a problem involving the phasor diagram of an angle modulated signal whose equation is given by $$s(t) ...
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1 answer
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Phase plot from impulse response function does not match that of the frequency response function

I have a first order linear filter $$ H(s) = \frac{1}{1+\tau\,s} $$ With the impulse response function, found using the inverse Laplace transform as $$ h(t) = \frac{1}{\tau}\,\exp\left({-\frac{t}{\tau}...
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