Questions tagged [phase]

A quantity representing the fraction of cycle of a periodic signal, usually represented as an angle.

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Interpolation of STFT between time and frequency bins

I am trying to identify and remove airplanes in a time series obtained at a radio meteor receiver. Here we have a spectrogram which displays the power content of my signal as a function of frequency ...
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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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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 ...
user6522399's user avatar
3 votes
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Amplitude and Phase Recovery of a Signal Embedded in Linear Signal with Noise

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 ...
dansignal's user avatar
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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 ...
Somesh Ganesh's user avatar
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3 answers
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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 ...
snatchysquid's user avatar
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How to sum amplitudes only without distorting the signal?

I do audio signal processing using Python (scipy, numpy etc.) I'm trying to "mix" 2 audio signals in a way that reduces phase canceling as much as possible. So I do an FFT of the 2 signals, ...
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Synchronization of two noisy sinusoidals signals

I have two noisy sinusoidal signals and I am currently investigating solutions to synchronize them using python. Here is an example I made to illustrate my goal, supposing that I generate these two ...
Marc Schwambach's user avatar
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Stability of filters with negative phase delay, group delay, and positive phase

Lets assume I have an IIR filter with : bz = [1.0195 0 0]; az = [1 0.0166 0.0020]; fvtool(bz,az) The filter is stable as i can see. If you check the phase delay ...
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Understanding Phase noise of a Hard Limited Sine Wave

I need help in understanding the frequency spectrum of a sine wave with phase noise that has been hard limited. Background: Typically, textbooks define phase noise for a sinewave, however in many ...
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How to find the noise power in my simulation

I am currently working a tricky communication chain that I want to simulate into Matlab. The chain is like a classic BPSK modulator/demodulator chain, but where the BPSK modulated signal has been ...
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GPS CDMA signal acquisition (BPSK modulation)

Sorry, this may be a rookie question: I have a CDMA gps communication in BPSK. Codes have a duration equal to $1\ \text{ms}$ and their length is 1023. At the carrier frequency ($f_c = 1.57524\ \text{...
Stefano's user avatar
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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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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 "...
Astor Florida's user avatar
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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 ...
John Jin's user avatar
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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 ...
Tudelft_Res's user avatar
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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 ...
jiandingzhe's user avatar
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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 (...
SmithMcPatrick's user avatar
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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 ...
user4789322's user avatar
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1k 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?
Manoj Kumar's user avatar
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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 ...
user1172468's user avatar
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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, ...
mirosval's user avatar
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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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Phase correction using second order all pass filters/LMS with Wiener-Hopf equations

I am working on phase correction algorithms. Can anyone help me understand how can the following diagram be used for phase correction: Additionally, for a channel function suggested How determine the ...
Deanna77's user avatar
2 votes
1 answer
557 views

Phase difference calculation for non divisible sample rate to frequency

I am learning DSP and I am trying to simulate a simple phase difference calculator between two sinusoidal signals using GNU radio. My flowchart looks like this: As can be seen on the chart, one of ...
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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 ...
nada's user avatar
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Calculating phase difference between two vibration signals

The idea behind this question is for misalignment fault we say vibration signals across the misalignment are out of phase. If the signals are just sinusoidal signals with one frequency calculating ...
Genos's user avatar
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How to calculate Coarse & Fine Carrier freqeuncy Offset using Short and Long training Preamble respectively! Equations not understood

I am transmitting an OFDM signal. According to 802.11a Standards, I am using Short and long training Preamble each has length of 160 samples for time and frequency synchronization. According to Essam ...
Walkürie's user avatar
1 vote
1 answer
93 views

Complex samples in OFDM signal, after fft-block at the receiver, have rotating amplitude towards zero even after phase correction

First of all, please consider my lack of experience/background in real time transmission using SDR especially if my explanation was expressed technically well.enter image description here I have ...
Walkürie's user avatar
1 vote
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OFDM complex symbols have dynamic phase shift after the fft-block & before the BPSK demodulator at the receiver ,

I have transmitted and received an OFDM-signal using the same ADALM-Pluto-SDR's Tx/Rx Antenna. I have used BPSK baseband modulation with symbol freq=312.5 KHz, L (length of ifft)=64, fsampling=fsym*L=...
Walkürie's user avatar
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Is lock-in amplifier a correct approach?

I have a noisy signal which is the voltage output from a photodetector circuit. I have researched about extracting signals, and found that lock-in amplifiers are one of the main approaches for the ...
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Loss of Resolution When Shifting Up With FFT / Phase Vocoder Pitch Shifter (Compared to Shifting Down)

I am working on a project writing a realtime FFT / phase vocoder based pitch shifting algorithm in C++. In development, I notice that shifting down has much better audible pitch tracking and ...
Emmett Palaima's user avatar
1 vote
0 answers
55 views

Phase rotation compensation in AOA

We are using $4 \times 4$ corehw antenna array with nrf52833 mcu as the receiver and nrf52833 as transmitter. When working on AOA Direction Finding, we found that each element in the antenna array has ...
user68463's user avatar
1 vote
1 answer
199 views

phase unwrapping relative to a reference

I have samples of wrapped $(-\pi,\pi)$ phase from a bandlimited signal $A(t)\cos(\pi\omega t + \phi(t)+\theta_0 )$ Frequency is constrained by very regular physics and I know a preliminary guess $\hat{...
Eli S's user avatar
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How to calculate phase estimation error

I am working on speech enhancement and I want to compare the phase and magnitude between two signals. I compute the STFT for both, and comparing the magnitudes is easy via mean-squared error or some ...
Mirao Da Silva's user avatar
1 vote
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30 views

What could be the cause of oscillating differential phase between a 2 channel audio signal

Test Setup I have two i2s microphones (INMP441) on a common clock. They are designated as the left and right channels with a sampling rate of 22050Hz. The generated signals are stored as WAV files and ...
Grabt234's user avatar
1 vote
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29 views

Depth estimation using phase shifted sine waves

For 3 phase shifted sine waves using the projected pattern: I = sin(x + δi) where δ ∈ [-2pi/3, 0, +2pi/3] which is then projected onto a scene. The resulting image is captured with a camera. I am ...
Arun's user avatar
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How to get correct phase values of the signal using Recursive Discrete Fourier Transform

Question I'm trying to understand the relation of the result of the recursive DFT to the original signal. I have a signal with a sampling frequency of 4000 Hz and the recursive phasor estimation ...
sakayevas's user avatar
1 vote
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131 views

Deriving the IF phase equation of FMCW

My understanding of the FMCW was limited to one chirp and was mostly focused on frequency analysis. (Mostly built upon this answer) I wanted to expand my understanding to multiple chirps and was ...
Moses Kim's user avatar
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numerical time differentiation in GNURadio

I'm hoping to put together a cheap modulation monitor for wideband FM radio using an rtl sdr usb, on the FCC website, it's listed that the modulation percentage for an FM station is the actual ...
Jacob's user avatar
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Adding $n\pi$ to the phase when estimating the phase velocity of a sound wave through a material

Setup I'm estimating the phase velocity in a wooden table by using an actuator and 3 sensors. The actuator sends out a chirp and on the table there are 3 accelerometers with distance $d$ between them. ...
vegiv's user avatar
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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. ...
abdullah A's user avatar
1 vote
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45 views

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 ...
Trym's user avatar
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1 vote
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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 (...
Liz Salander's user avatar
1 vote
0 answers
43 views

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 ...
BandW's user avatar
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Self Quadratic Phase Coupling || What does it really tell us?

I am working on a beginner kind of project, and after processing some data and plotting a lot of bispectrum plots, I found out that a lot of them had peaks on the diagonal fx = fy (where fi denotes ...
SuperMario's user avatar
1 vote
0 answers
73 views

Phase relationship of cosine components in real signal using DFT

Background Info I have a real signal comprised of 8 frequencies 400Hz-680Hz in 40Hz increments. The signal is generated from 8 cosines of equal amplitude (A=1) and phase (Phase= 0rad), summed together....
Jacob Calvert's user avatar
1 vote
0 answers
66 views

Can an unwrapped phase lag diagram have values beyond $-\pi$ to $\pi$?

I have a PLL that tracks the phase lag of a resonance system. When unwrapped, my system's phase lag has values beyond $-\pi$ to $\pi$. After unwrapping phase lag, are there any bounds on the phase ...
ExactPlace441's user avatar
1 vote
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Why do we not encode frequency in 3 dimensions in MRI?

If I understand correctly, to select a particular slice (of an object, during an MRI scan) that is orthogonal to the direction of the main magnetic field applied, we apply a magnetic field that varies ...
Adriaan Berger's user avatar
1 vote
0 answers
74 views

Hilbert Transform on split datastream produces phase flip

this is my first post here! I'm trying to do phase correction on a signal from a linear CCD (2048 pixels, 10bit per pixel, 250kHz linerate) in an FPGA. Therfore I need to generate an analytical ...
Konstantin Werner's user avatar