Questions tagged [phase]
A quantity representing the fraction of cycle of a periodic signal, usually represented as an angle.
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Phase synchronization in BPSK
In BPSK for demodulation at the receiver end we do phase recovery between received wave and carrier wave. We can find the phase difference between the carrier and received waves using :
PLL
And ...
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How to build a phase shifter with arbitrary phase shift
Fred, a DSP engineer, goes to his favorite DSP store to do some shopping.
Fred: Hi, I'd like to buy a phase shifter.
Shop assistant: Hmm, what exactly do you mean?
Fred: Well, you know, if you put ...
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Negative group delay and envelope advance
I am having a doubt reading about delays in signal processing.
Let there be an input to a LTI system with frequency response $H(f)$, given signal $x(t) = a(t)\cos(2\pi f_ot)$, where $a(t)$ is a ...
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What is the difference between phase delay and group delay?
I'm studying some DSP and I'm having trouble understanding the difference between phase delay and group delay.
It seems to me that they both measure the delay time of sinusoids passed through a ...
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How to circularly shift a signal by a fraction of a sample?
The shift theorem says:
Multiplying $x_n$ by a linear phase $e^{\frac{2\pi i}{N}n m}$ for some integer m corresponds to a circular shift of the output $X_k$: $X_k$ is replaced by $X_{k-m}$, where ...
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What exactly is a 90 degree phase shift of a digital signal in FM demodulation appraoches?
I am working on an FSK demodulator (1200/2200Hz, 1200 baud) featuring a 90 degree phase shift operation. I don't exactly understand what 360 degrees mean for a digital signal.
My sampling frequency ...
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FFT Phase interpretation of input signal with non-integer number of cycles in FFT window
It is known that if we take the FFT of a signal at such a frequency which has non-integer number of cycles in the sample window we get different value of phase even if the original signal was at phase ...
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How to perform carrier phase recovery in software?
What are the options for recovering the phase of a BPSK signal in software? The only resources I can find online contain circuit diagrams – there seems to be no one willing to explain this to people ...
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Calculate and interpret the instantaneous frequency
I'm new to the principle of calculating the instantaneous frequency, and came up with a lot of questions on it. You find them all in a bullet-point list at the end of this text. The text might be a ...
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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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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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phase difference detection
For application of syncing sampling clock phase to carrier phase of received signal where the received signal is sampled with 10 times the carrier phase and modulated with the PSK shown in the figure (...
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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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Can a causal filter without phase shifts exist?
When I was studying dispersion of refraction index in semiconductors and dielectrics, my professor tried to explain that if a filter (like a dielectric absorbing some light frequencies, or an electric ...
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What is an Intuitive Explanation of the Phase of a Signal
I understand that the meaning of the phase response of a system is simply how much the system delays a frequency component. However, I do not find an intuitive explanation for the phase of a signal. ...
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What effect does rotation in the spatial domain has on phase in Fourier transforms?
More precisely, let's say I apply a 45 degrees rotation to an image (in the spatial domain) say, in Matlab :
Ir=imrotate(myImage,45,'crop');
FT_I=fft2(I);
In the ...
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Minimum phase FIR method
I am trying to make a minimum phase filter (in wxMaxima) according to these steps:
first create a "normal" FIR (a simple sinc, wc=0.4, random example, but in the pictures a remez with Octave)
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Should the phase coefficients of the DFT of a real, even input signal all be zero?
The phase coefficients of a real, even input signals should all apparently be $0$ or a multiple of $\pi$. That's a property of the DFT I've learned about in the Audio Signal processing course on ...
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Phase difference between signals sampled at different frequencies
I want to know that if it is possible to measure the relative phase difference between a signal that has been sampled at two different locations with different sampling frequencies? Also can that ...
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PLL for Phase Demodulation and Carrier Tracking
I've been playing around with using a PLL for phase demodulation and it's working pretty well. The PLL locks to the carrier and the error term is the demodulated message signal. However, depending on ...
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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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How can a filter have zero group delay?
If you put a wave packet through the passband of a 1st-order low-pass filter, it will be delayed by the group delay of the filter, and remain the same amplitude, right?
If you put the same wave ...
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Best method to extract phase shift between 2 sinosoids, from data provided
I have been asking around if the way I was extracting phase shift (lag) was correct, and I ran into some trouble.
So in general, given 2 arrays of data of the same length, representing:
the input ...
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Converting from a phase response to a group delay response and vice-versa
I'm trying to figure out how to convert any phase response to the corresponding group delay response.
Is there a way to do that, and vice-versa if possible?
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Phase measurement
I have a problem with phase measuring.
I'm acquiring two signal with a USRP (complex signals) with a coherent generator and I want to measure the phase different between them.. One is at 150Mhz and ...
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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 ...
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Understanding the phase in DFT
Although using regularly the FFT algorithm to compute DFTs, I don't really understand how the phase part works.
e.g. in Matlab:
...
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Matlab code for Simulating of Phase Noise for OFDM systems [closed]
I am trying to simulate phase noise for OFDM systems.
I have been reading about phase noise, some literature suggests that phase noise is cumulative as follows:
$\phi(n)=\phi(n-1)+\omega(n)$
where $\...
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Phase Correlation - Poor Performance on Noisy/Blurred Images?
I have successfully tested 1D phase correlation algorithm to determine vertical shift between two synthetic images.
When I moved to real images, however, it is not able to detect translation at all (...
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How important is it to use power of 2 when using FFT?
Here is the problem. I have a 2D array of data, first column represents the time data and the second column represents the sinusoidal response data, based on the time data. I apply fft and I get my ...
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What is the difference between phase noise and frequency noise?
I'm reading Audoin and Guinot's The Measurement of Time: Time, Frequency and the Atomic Clock, and ran across a confusing an interesting passage (Section 5.2.5, pp 72-73):
The physical origins of ...
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baffled by fft phase spectrum!
A very simple MATLAB experiment:
f = 200;
fs = 1000;
t = 0: 1/fs : 1;
x = cos(2*pi*f*t);
plot(angle(fftshift(fft(x))));
And here's the output:
Now, made ...
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Meaning of Phase response of a filter? In simple words?
What is meant by phase response of a filter? Often it is associated with restoration of signal shape,so if a filter has linear phase response, its output looks like input otherwise output is ...
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Removing a sinusoidal artifact from a set of movie frames
I am doing some post-hoc analysis of a dataset consisting of a series of movie frames that are contaminated by a strongly periodic artifact. I would like to remove this artifact from my frames.
For ...
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Phase Locked Loop Basics
I am trying to better understand discrete-time PLLs. I drew a picture of a simple feedback system here:
I want to be able to describe and understand the system at v(t) and y(t). I found a fairly good ...
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How does time shift correspond to phase change in a discrete signal?
I was watching this video where the presenter remarks:
For a discrete signal, time shift corresponds to phase change in a discrete signal but not vice versa.
I was trying to figure out how this ...
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Group Delay for Hilbert Transformer and Resulting Dispersion
An ideal Hilbert Transformer shifts the phase for all positive frequencies by $-\pi/2$ and all negative frequencies by $+\pi/2$ while maintaining constant magnitude everywhere. Group Delay is the ...
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Calculate the magnitude and phase of a signal at a particular frequency in python
I have a signal for which I need to calculate the magnitude and phase at 200 Hz frequency only. I would like to use Fourier transform for it. I am very new to signal processing. And this is my first ...
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Signals cross-correlation
I am trying to measure phase difference between two received waves which are recorded by two separate PC's (microphones). The two PC's starts recording at the same time, then I make a sine wave sound ...
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Fast phase calculation
I need to detect the PSK modulation posted on my previous post (phase difference detection) with 8 to 16 phase constellations (depending on selected baud rate) over a max $60^\circ$ PSK phase range. ...
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Correcting phase response of a signal
I have a sensor that applies a frequency dependant phase alteration to my signals. I'm trying to find a way to correct these phase responses using an FIR filter. Essentially, I'm looking for methods ...
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What does the term phase actually mean?
I am new to seismic data processing and I really have no understanding of the term 'phase'. So, could anybody give me a simple explaination of the term?
Thank you
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proving that a log gabor filter has 0 DC offset
I have read somewhere online that the log gabor filter has an advantage over the gabor filter, in the sense that it has 0 DC component. How do you prove this property mathematically? Thanks in advance....
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Discrepancies between FFT-based Hilbert Transform and FIR filter results
I compared the results of Hilbert Transform as provided in scipy.signal.hilbert() (which is uses I/FFT as you can see in the source code) with its approximation implemented as FIR filter using coeffs ...
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Beyond "mid-side": decompose an audio stereo recording (coincident microphones) into Mid + 45° + 90°
Context: I have done in the past stereo recordings in XY position (coincident microphones):
from a source far from at least 20 meters (example: piano in a big reverberant building).
Since the ...
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minimum-phase phase via Hilbert transform returned values
Following my previous question: HRIR Minimum phase I managed to compute the minimum-phase phase of a FIR filter (in my particular case, HRTF filters).
However I am not sure of the phase values ...
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Algorithms to re-spatialize a stereo recording audio signal?
Let's say we have an audio signal stereo recording, made for example with a XY microphone positioning:
Which algorithms can be used to "re-spatialize" this recording, i.e. try to virtually &...
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Transform linear-phase FIR to minimum-phase FIR
Given a FIR filter (non-causal) with phase zero and real coefficients given by $$H(z) = \sum_{n=-M}^{M}h[n]z^{-n}$$ with ripple $\delta_2$.
How can I obtain a filter $H_{{\rm min}}(z)$ of minimum ...
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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 ...
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find phase greater than 2*pi in MATLAB
I'm working on extracting the phase information in a given signal in MATLAB. I've the following vector;
...
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