# Questions tagged [phase]

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

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### Phase equalization for a notch-like filter

Consider the following filter with DC-notch-like characteristics: $H(z) = \frac{1-2z^{-1} + z^{-2}}{1+a_1z^{-1}+a_2z^{-2}}$ where $a_1= -1.99396970948671$ and $a_2=0.994002716421032$. The magnitude ...
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### Phase Slope Distance Calcuation

After trying to implement IFFT algorithms for phase-based ranging, as outlined in this very interesting and descriptive blog post; I've been getting horrendous results (orders of magnitude inaccurate),...
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### Phase shift between X and Y components of the same wave

I was told to post this question here, originally posted on Overflow. I have two signals, I1 and I2, which were acquired from a white light source in a spectrally resolved interferometer with a ...
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I am currently studying the topic of oscillator phase noise in frequency modulated continuous wave (FMCW) radar. In my specific case, the radar is implemented on an FPGA (AMD RFSoC). Thus, the echo is ...
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### Baseband downconversion without imaging

I am a high school intern at a company employing heavy DSP and trying to learn the basics from the ground up. One feature of a test application I'm creating is the ability to zoom an FFT graph and ...
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### LED image phase projection

Say you have a goal image G with a phase called phase G. Can you physically construct and project phase G, or is phase not something physical? Like, can you set up an array of LEDs to project the ...
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### How do you interpret the sign (positive, negative or zero) of the phase spectrum?

How do you interpret the sign (positive, negative or zero) of the phase spectrum of: 1)a digital filter (the phase spectrum of its frequency response aka phase response of the filter). 2)a signal in ...
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### PLL Phase Error Detectors for non-bandpass-communication type signals

I'm quite familiar with PLLs for bandpass signals (e.g., GPS) which operate on IF or complex baseband signals. However, I now have a phase tracking problem where the signal is not necessarily ...
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### Are integer multiples of a frequency in an FFT necessarily in phase?

I performed a FFT on a signal and the most prominent frequency at about 0.5 cycles/time only makes up about 6% of the total frequency distribution, which is pretty low for my purposes, so I was ...
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### Jitter model does not behave as expected after FFT

So I'm currently trying to understand the relationship between jitter and phase noise. To help my understanding I did write a little simulation in matlab. I used this model in the time domain, relying ...
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### Finding the right phase offsets for minimizing the highest absolute value of a sum of sinusoids

suppose I have a sum of cosine waves. Their frequencies are 500 Hz, 501 Hz, 502 Hz and so on, all the way up to 900 Hz. The important thing here is that the amplitude of the slowest one and of the ...
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### Time delay vs phase ramp, group delay and phase delay

I need to apply a phase ramp in the frequency domain to a signal in order to apply a delay to it in the time/digital domain. However, I am confused by the fact that if I convert the phase ramp into ...
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### Linear Phase in equiripple filters

How come equiripple filters are symmetric/anti-symmetric in time, but do not posses linear phase, but only piecewise-linearity? Do not all FIR+symmetric/anti-symmetric have Generalized linear phase?
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### Iterative GA algorithm For Antenna Pattern Matching

The following code creates a cosecant squared radiation pattern. There are phases and an amplitude_norm_V vector which are the coefficients of an Array Factor (AF) expression as the response of an ...
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### Wideband phase vs time delay beamforming correction

I am studying a 1D beamforming for wide-band signals, so that applying only phase weights to each individual antenna would steer the beam for the central frequency. For other frequencies the steering ...
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### Does calculating the phase margin when the phase is positive has any meaning?

I want to calculate the phase margin and the gain margin of my transfer function to have an idea about the system's stability. The transfer function is quite complicated since it contains an ...
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### Array factor phased array beam steering problem

I have created exactly the array factor formula in matlab . But when i add the beam steering delta member it does nothing to the main lobe. Why it stays the same? Thanks. ...
1 vote
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### Why in 2D Fourier Transform phase seems to be more "useful" than magnitude?

In 1D signals f(t) (e.g. a sound signal - independent variable t-->time) when we want to use informations from the Fourier transform F(ω) in order to reconstruct the signal, using the magnitude |F(...
1 vote
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### In the frequency domain of a phase-shift keyed signal, why there are are prominent frequency components which are multiples of sampling frequency?

In the frequency domain representation of a digital phase modulated signal, why there are prominent other frequency components which are multiples of the sampling frequency, other than the main ...
51 views

### What exactly is the carrier phase in a RINEX file?

RINEX files are containers for preprocessed data in GNSS receivers. I want to know what exactly the 'carrier phase' means. As far as I can tell, the carrier phase is simply the phase (that is, a value ...
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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 ...
1 vote
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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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### 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 ...
1 vote
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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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### 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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### 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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### 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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### 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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### 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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### 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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