Questions tagged [phase]
A quantity representing the fraction of cycle of a periodic signal, usually represented as an angle.
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Method to extract a phase between input and output of a nonlinear system
I have a nonlinear (blackbox) system which gets a singular frequency (f) signal as input:
input = A*sin(2*pi*f) + B
And I get an output signal, which has ...
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First-order allpass filter coefficient calculation
Given the first-order IIR allpass filter depicted below, I would like to calculate the coefficient $a_1$ such that a phase shift of $\frac{\pi}{2}$ occurs at a desired frequency $f_\mathrm{c}$ (the ...
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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 ...
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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{...
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Why does the griffin lim algorithm work?
the griffin lim algorithm works to reconstruct audio from a magnitude spectrogram, but i don't understand how reusing the same spectrogram every iteration with noise can produce decent sound
How from ...
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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 ...
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How to convert the phase noise spectrum density to frequency spectrum density?
Following the answer in this post: Phase noise and frequency noise relationship, I can calculate the phase noise spectrum density with the unit from $\frac{dB_{c}}{Hz}$ to $\frac{rad}{\sqrt{Hz}}$. ...
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Finding phase of frequency response as a function of frequency
I am trying to calculate manually the phase of the frequency response of an LTI system as a function of frequency and plot the results. The original system is described as $y[n]=0.1(x[n]-x[n-1]+x[n-2]$...
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Phase correction of a received signal
How is it possible to correct the possible phase distortion of a typical signal which has been received by an antenna and passed through different analog elements including an amplifier and a band ...
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How to get defect image from unwrapped phase image?
My problem is how to get the third and fourth image using first and second image.
The first one is unwrapped correspondence image in x direction.
The first one is unwrapped correspondence image in y ...
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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=...
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Why is the phase of the FFT not exactly 0 degrees for a cosine and 90 degrees for sine wave?
Let's say I have two signals. The first is a cosine wave and the second is a sine wave. Each oscillates at 0.01 Hz. The sample rate is 1 Hz and the length of time series is 1000 seconds. Each has an ...
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Does phase shift introduce high frequencies?
In PSK phase modulation scheme, the signal phase is shifted, hence it looks something like this:
I cannot understand why this doesn't introduce a set of unwanted high-frequencies, as the steep ...
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Extracting the phase using FFT without detrending
I'm trying to use FFT to extract the phase of the following signal:
This is just a function in the form of: m*t + 5*sin(2*π*f*t - π/4)
Is it possible to get the <...
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PLL in noise-free and noisy channels
I'm trying to evaluate the performance of PLL in compensating the phase noise in the absence and presence of AWGN noise, and the counterintuitive result I consistently get is that PLL performs better ...
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How to compute the direction/bearing of a vector time series in the frequency domain (i.e. as a function of frequency)?
I have a time-domain magnetic field, $\mathbf{b}(t)$, with components $b_x(t)$ and $b_y(t)$ where $x$ and $y$ denote orthogonal coordinate directions (i.e north and east, respectively). At each time, ...
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Probability distribution of phase of fourier transform of white noise, colored noise (1/f noise in particular)--- Definitions and standards
What is the probability distribution of phase of fourier transform of white noise and colored noise (1/f noise in particular) ? Is there a standardised definition?
Often, the colored noise is derived ...
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Variance of phase estimation using FFT as a function of SNR, frequency and signal length
I have looked at previous questions on this topic but I am still unsatisfied. I want to predict how accurately I can estimate the phase of a tone as a function of signal SNR, tone frequency, and the ...
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Correlated phase noise
I am trying to find a mathematical model to understand the correlated phase noise.
Here, I see the reference phase noise is almost the same after up-conversion and then down-conversion. How does ...
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Phase of matched filter for chirp signals
I am using the following system: Ultrasonic chirp signals with central frequency 100kHz are being transmitted using ultrasonic sensor. After the transmission through the medium(air/solid/liquid/...
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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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Lock-in Amplifier: How to improve the output of lock in amplifier?
I tried to extract a pure signal from the noisy signal using a lock-in amplifier with the help of python code.
The output is from a photodetector circuit.
These are the reference signal, expected ...
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Averaging a Signal with a delayed version of itself
I am working on a problem that requires interpolating between two music files. One music file is very similar to a delayed version of the other.
I would like the 'average' of the two signals to sound ...
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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 ...
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How to calculate the phase difference between two squarewaves of same frequency but different dutycycle?
I have two squarewaves of the same frequency but with different dutycycle. How can I calculate the phase difference between the two?
I know that for sinewaves one can use the correlation coefficient, ...
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Design a Real FIR with arbitrary Phase Response
Intro
My question is related to this one: Correcting phase response of a signal.
I need to design an FIR low-pass filter with real coefficients for data received from a sensor. An additional ...
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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 ...
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How can I apply a phase shift to an LFM pulse?
I am modelling radar scenarios in python and am trying to make a model which retains phase information. To do so, I'm envisioning something which works like this:
Generate samples of an LFM waveform ...
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Extract Sine Phase and Amplitude - accurate and robust method
This is a followup question to one I asked earlier based on the chat after the answer given by @hotpaw2, and cross-posted from stackoverflow since it was suggested it is more relevant to DSP. I have a ...
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Average of a set of transfer functions: how should I treat the phase?
I have a set of transfer functions obtained by impacting an instrumentation hammer against a mass, measuring the acceleration on a set of accelerometers; the result is shown below. I want to get a ...
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How to explain the ripple in this graph?
Hi everyone I need your help to understand this phase response would you please share your ideas?
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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 ...
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Low-pass Filter with constant phase response
I would like to design (e.g. in GNU-radio) a low-pass filter where up to the cut-off frequency the phase-response is constant (I do not mean a "linear-phase response"). The rationale is to ...
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Can someone explain the phase spectrum of a sinc function?
The Fourier transform of a sinc function will result in a rect function. Suppose I have a discrete time-domain sinc function with a frequency of $\omega_0 = 0.1$ Hz and amplitude of $A = 10^{-3}$:
If ...
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Why extracted minimum phase component have inverted phase?
I'm using Octave code to extract minimum phase, but this minimum phase has became inverted phase acording to original signal, What is goin wrong?
Resault here I have shifted main signal about 48 ...
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Calculate Phase Shift Using FFT
I'm not a specialist in this field and learnt FFT fairly recently.
I want to calculate phase difference of between 1 MHz signals sampled at 4 MHz. The sample counts are both 144. I think the ...
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Introducing periodic jitter to a clock
This question is about the ideal digital clock. Lets consider an ideal clock with 0 raise time and 0 fall time i.e. perfect square wave. As shown in the diagram below. Let the original clock period be ...
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Phase Unwrapping Behaving Oddly For Optics Simulation
In short, I am coding an optics simulation for an experiment I am running. There is a point where I perform a Fourier transform on my incoming signal and want to extract the phase; however, I get ...
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Pitch tracking and phase
I wish to control a simple pitch tracker using my voice. So far I have experimented with fft and yin. I am extracting the frequency and amplitude in real time. I then feed these into:
...
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How to compensate for rotational offset for Steering vector of a phased antenna array
I am working with antenna phased arrays for direction finding. According to the manufacturer of the antenna some elements of the uniformed rectangular array (URA) have a rotational difference. This ...
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Generating IF signal for FMCW radar
I am trying to generate a signal that represents mixer output of FMCW radar. I am using MATLAB and already tried out this tutorial. There, Phased Array System Toolbox is used to showcase how FMCW ...
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Why is there a difference in the phase when using fft versus a manual DFT on a cosine signal?
Apologies if this is a duplicate, but I can't find a good answer anywhere.
If I have a time-domain cosine signal of the form:
$$x(t) = A\mathrm{cos}(\omega_0 t)$$
Then this will result in an Fourier ...
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Finding phase of a received signal using spectrogram function
I am trying to find the phase of my dataset between a range of frequencies. I can't post my code or data but generally speaking, the frequencies range from 10 to 100kHz and I need the phase between 20 ...
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how to log phase of NWC Australia 19.8KHz in a file in python
First I am very new in this field,and i am doing a college project and i stuck at determining phase of msk signal which is transmitted from a radio stations called NWC Australia 19.8Khz , so let me ...
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Modelling phase noise for self-heterodyne method
I am trying to model the phase noise $\phi(t)$ of laser used in self-heterodyne method using python code. The noise is time-dependent. The noise follows the condition that
$$\langle(\phi(t)-\phi(t-\...
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Phase Spectrum of Signals
I did fft of a fish's trajectory, because it looks periodic and I tried to find the frequency. However, I can't understand what does the phase spectrum below represent. Does this lower left to upper ...
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Phase compensation using IIR allpass filters
As an exercise with IIR allpass filters, I am trying to compensate the phase of a lowpass Linkwitz-Riley filter using the Matlab integrated function iirgrpdelay.
The code I am using is the following:
<...
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Filtering after a phase domain ADC
While researching receiver architectures for the demodulating constant envelope signals like a GFSK, I stumbled over the concept of phase domain ADCs, where after
$$\boxed{\text{LNA}}{\longrightarrow}\...
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Phase Unwrapping Issue of IQ data sample in Radar Signal Processing
I am doing radar sensor signal processing.
The radar sensor gives iq data corresponding to the range (sweeps).
I want to detect micro motion so that phase analysis is used.
Sweep is the distance ...
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Integrating CWT around nominal frequency with amplitude and phase
I have a real signal f sampled at 96Hz composed of clusters of harmonics scattered tigthly around evenly central frequencies close to 1Hz and 2Hz (multiples of 0.966Hz) that I'll call features. These ...
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