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Question: <p>I am working on analysis of baby cry signal. fundamental frequency(Fo) of signal is already estimated using auto correlation and cepstrum analysis. cry signal is inputted in .wav format. now i want to do short time fourier transform analysis of same signal inorder to find variations in fundamental frequenc... | https://dsp.stackexchange.com/questions/22558/short-time-fourier-transform-analysis-of-newborn-baby-cry-signal |
Question: <p>I'm trying to detect rapid changes in a one-dimensional signal say <span class="math-container">$[0,1]\ni t \mapsto f(t) \in [-1,1]$</span>. By rapid changes, I mean corner points, edges, or sharp transitions at a point for example the signal switches from a value <span class="math-container">$-1$</span> t... | https://dsp.stackexchange.com/questions/86782/a-mathematical-justification-of-discontinuity-detection-using-stft |
Question: <p>I am performing time-frequency analysis on electrophysiological data with complex morlet wavelets. Each decomposition in the attached figure shows <em>total power</em> following the onset of a stimulus (top row) or preceding an eye movement (bottom row). There is a broadband, transient increase in power fo... | https://dsp.stackexchange.com/questions/49229/isolating-frequency-specific-oscillation-from-transient |
Question: <p>After a lecture on harmonic analysis and time/frequency methods, I reconsidered the Gaussian kernel, defined in continuous time. </p>
<p>It is unimodal and symmetric, and its continuous Fourier transform is another Gaussian, thus unimodal and symmetric (from <a href="https://stackoverflow.com/questions/53... | https://dsp.stackexchange.com/questions/36247/conditions-for-symmetric-and-unimodal-windows-in-both-time-and-frequency-domains |
Question: <p>I am reading </p>
<p><a href="http://users.rowan.edu/~polikar/WAVELETS/WTpart3.html" rel="nofollow noreferrer">The Wavelet Tutorial</a></p>
<p>Part III
MULTIRESOLUTION ANALYSIS
&
THE CONTINUOUS WAVELET TRANSFORM</p>
<p>by
Robi Polikar </p>
<p>The author explains about the following fig and says;</p... | https://dsp.stackexchange.com/questions/9319/trying-to-understand-wavelet-transform-frequncy-time-diagram |
Question: <p>my research focuses on wideband spectrum sensing. I'm currently reading <strong>"A Wavelet Tour of Signal Processing" by Stéphane Mallat</strong>, and I find it very rich and foundational.</p>
<p>My current approach is to:</p>
<p>Read Mallat’s book carefully to understand wavelet theory, time-fre... | https://dsp.stackexchange.com/questions/96565/is-it-a-good-idea-to-start-with-wavelet-theory-before-reading-recent-spectrum-se |
Question: <p>I want to do time-frequency analysis of a signal. So i decided to use <a href="https://docs.scipy.org/doc/scipy-0.16.0/reference/generated/scipy.signal.spectrogram.html" rel="nofollow noreferrer">spectrogram</a> function from scipy. This function returns, three parameters f,t,Sxx. I am using below arguemen... | https://dsp.stackexchange.com/questions/46516/scipy-signal-spectrogram |
Question: <p>I want to do frequency analysis of audio data, basically trying to figure out what the notes are in a song algorithmically. The standard approach is to decode the MP3 into PCM data and run it through an FFT. However, notes below around middle C require too much precision for an FFT to work well. Since t... | https://dsp.stackexchange.com/questions/58403/extract-frequency-data-from-mp3-file |
Question: <p>For linear time-frequency representation, the resolution is limited by <a href="https://en.wikipedia.org/wiki/Gabor_limit#Signal_processing" rel="noreferrer">Gabor limit</a>. However, if interference is allowed, the resolution may be higher. What is the possible resolution in such a case? In "Electroenceph... | https://dsp.stackexchange.com/questions/17058/does-wigner-ville-distribution-provide-the-highest-resolution |
Question: <p>Suppose a signal is a superposition of multiple intrinsic-mode-type (IMT)
functions, say
<span class="math-container">$$f(t) = \sum_{i=1}^n A_i(t)e^{i\varphi_i(t)} $$</span>
Why is the separation condition of <span class="math-container">$f(t)$</span> be
<span class="math-container">$$\forall i,j \quad|\va... | https://dsp.stackexchange.com/questions/81169/the-separation-condition-of-a-multi-component-signal |
Question: <p>I'm reading the text book "Time-Frequency Analysis" by Leon Cohen and I've made my way through a decent portion. There is however a conceptual issue I keep coming back to. The book states:</p>
<blockquote>
<p>If we consider $\lvert s(t)\rvert^2$ as a density in time, the average
time can be defined in... | https://dsp.stackexchange.com/questions/24904/defining-an-average-in-time-for-a-density-in-time |
Question: <p>I am looking for a good introduction to wavelets and wavelet transforms.</p>
<p>that covers the following: Vector Spaces – Properties– Dot Product – Basis – Dimension, Orthogonality and Orthonormality – Relationship Between Vectors and Signals – Signal Spaces – Concept of Convergence – Hilbert Spaces for ... | https://dsp.stackexchange.com/questions/14109/need-to-learn-wavelet-suggest-steps-and-resources |
Question: <p>Imagine transfer function obtained by Laplace transform, for example:</p>
<p>$G(s) = \dfrac{1}{s+1}$</p>
<p>Now, I would like to do some frequency analysis, so I replace the $s$ with $\omega i$ (let's consider this operation valid for this example).</p>
<p>What is the unit of the $\omega$? So far what I... | https://dsp.stackexchange.com/questions/43733/meaning-and-unit-of-frequency-in-laplace-fourier-transform |
Question: <p>I am sending a 20Khz signal from my phone and capturing all the signals while doing exercise above it. Here I have a signal of a person doing "<a href="http://www.top10homeremedies.com/wp-content/uploads/2016/02/scissors-exercise.gif" rel="nofollow noreferrer">hand scissors exercise</a>"</p>
<p>I am doing... | https://dsp.stackexchange.com/questions/35297/any-examples-of-analysis-in-time-domain-to-extact-information |
Question: <p>I've been looking to merge two datasets I have, that capture instances of the same phenomenon using two different recording tools. Both are multichannel electrical signals, but the recording tools have very different properties.
I want to standardize those measures to make them hardware independent, but sa... | https://dsp.stackexchange.com/questions/82892/standardizing-signals-from-the-same-experiment-setup-with-different-recording-to |
Question: <p>The spectrogram of a signal throws away the phase information, but it is said to be possible to reconstruct the signal only from the spectrogram [1] via
$$s(t) = \frac{1}{2\pi s^*(0)}\int_{-\infty}^{\infty}\frac{M_{SP}(\theta,t)}{A_h(-\theta,t)}e^{-j\theta t/2}d\theta$$ where $M_{SP}$ is the chariteristic ... | https://dsp.stackexchange.com/questions/47820/reconstruct-signal-from-its-spectrogram-only |
Question: <p>What is the best "Signals and systems" Module Online course/resource/Youtube playlist?</p>
<p>FYI, this request is for a Final Year undergrad following Bachelor's degree in EEE.</p>
<p>I have checked Neso academy, but its too long and can be frustating to complete it, also it doesnt cover most of... | https://dsp.stackexchange.com/questions/97832/what-is-the-best-signals-and-systems-module-online-course-resource-youtube-playl |
Question: <p>I have a vibration signal coming from a motor measured from accelerometer (<strong>Irregular Time series</strong>) and I need to use these signals for analysis purpose. </p>
<p><img src="https://i.sstatic.net/yNYDe.jpg" alt="pic2"></p>
<p>I am in need to transform this signal to some form for analysis pu... | https://dsp.stackexchange.com/questions/43157/analysis-of-vibration-signals |
Question: <p>How to show the time history of a signal down-sampled under the rates of 25Hz & 40Hz and find its DFT analysis using Matlab ? The sample signal is in a data file (<a href="http://www.filedropper.com/sensordata" rel="nofollow">sensor_data.mat</a>) its sampling rate is 1000Hz.</p>
<p>I can get the time ... | https://dsp.stackexchange.com/questions/23492/how-to-show-the-time-history-of-a-signal-down-sampled-under-the-rate-of-25hz |
Question: <p>I have a device (Large as typical PC casing) with a motor. There can be a condition that the device motor load is unbalanced and the device starts to move around the table and I need to detect this. For this, I have an accelerometer.</p>
<p>But the problem is that I can't come up with a reliable algorithm ... | https://dsp.stackexchange.com/questions/70179/accelerometer-data-analysis-without-fft |
Question: <p>I have been studying the Hilbert-Huang transform, which I understand is a frequency analysis technique that uses the adaptive IMFs basis components to decompose a signal using EMD.</p>
<p>I understand that frequency analysis techniques such as the STFT (short-time Fourier transform) and Wavelet transform ... | https://dsp.stackexchange.com/questions/64336/why-does-the-hilbert-huang-transform-not-suffer-from-the-uncertainty-principle |
Question: <p>What is Spectral entropy and spectral moments? I know what the normal entropy of a signal is! And also what are some good time-frequency features for the analysis of non-stationary signals?</p>
Answer: | https://dsp.stackexchange.com/questions/49809/spectral-entropy-and-moments-and-non-stationary-signal-processing |
Question: <p>I am currently working on a project which requires evaluating slow changes over time in the magnitude of a signal's high frequency (over 10 kHz) components.</p>
<p>This signal was acquired in tests with a 25.6 kHz sampling rate and in "batches": every minute, one second of data was acquired. This... | https://dsp.stackexchange.com/questions/87036/reconstruction-of-batch-acquired-signal |
Question: <p>I was studying the introduction to wavelets and its benefit over the frequency domain. I said that:</p>
<blockquote>
<p>Fourier analysis can't localize signals both in time and frequency
domain. Fourier analysis can localize signal in frequency domain very
well, but not so much in time domain. While... | https://dsp.stackexchange.com/questions/33474/fourier-transform-can-localize-signals-in-frequency-domain-but-not-in-time-dom |
Question: <p>Can anyone describe in a bit more detail or provide references to the techniques for simultaneous enhancements to time and frequency resolution described in a high level in <a href="https://youtu.be/BQRNPXkN6Ww" rel="nofollow noreferrer">HEAD acoustics International - Advanced FFT Analysis HSA - frequency ... | https://dsp.stackexchange.com/questions/82743/fft-with-high-time-and-frequency-resolution |
Question: <p>Defined as "negative DFT bins zero", when are such filters suboptimal for AM/FM extraction or related filtering? <a href="https://dsp.stackexchange.com/a/83991/50076">This answer</a> reads,</p>
<blockquote>
<p>[nulling] also has the worst performance compared to other methods such as windowing or... | https://dsp.stackexchange.com/questions/84638/when-is-perfect-analytic-filtering-discrete-suboptimal |
Question: <p>The big disadvantage of a DFT is that it has only frequency resolution and no time resolution. This means that although we might be able to determine all the frequencies present in a signal, we do not know when they are present. So we go for Wavelets.</p>
<p>My question is, What are the applications (othe... | https://dsp.stackexchange.com/questions/14404/why-we-need-frequency-and-time-information-at-the-same-time |
Question: <p>At a glance, the constant-Q fourier transform and the complex <a href="https://dsp.stackexchange.com/q/2114/29">Gabor-Morlet wavelet</a> transform seem the same. Both are time-frequency representations, based on constant-Q filters, windowed sinusoids, etc. But maybe there's a difference that I'm missing... | https://dsp.stackexchange.com/questions/6266/whats-the-difference-between-the-gabor-morlet-wavelet-transform-and-the-constan |
Question: <p>I have been reading about non-linear non-stationary signal analysis methods and it seems to do this type of analysis the go-to method is the Empirical Mode Decomposition (EMD), then Hilbert Transform (HT) to get instantaneous phase and frequency.</p>
<p>However I have been doing some analysis on a non-lin... | https://dsp.stackexchange.com/questions/59797/non-linear-non-stationary-spectral-analysis-methods-when-and-where |
Question: <p>The signal I'm studying has fundamental frequencies of 20 and 60 cycles per minute (shown in the Periodogram graph). It is straight forward to extract the peaks in the time domain belonging to the 20 cycles/minute frequency (both are circled), however the peaks associated with the 60 cycles per minute freq... | https://dsp.stackexchange.com/questions/59118/is-it-possible-to-extract-peak-locations-in-the-time-domain-using-help-from-four |
Question: <p>I want to write an algorithm in C++ which is capable of identifying specific features within a single song, e. g. the sound of a drum which is played 100 times during 5 min. </p>
<p><strong>State of the project</strong></p>
<p>So the first thing I did was to import my *.wav-file, perfrom a step-wise FFT ... | https://dsp.stackexchange.com/questions/36963/feature-recognition-within-a-single-song |
Question: <p>I'm new to python and I'm using it to analyse accelerations from an accelerometer ie. vibration analysis. For that I need to plot 2 types of diagrams:
1) Frequency map; frequency and time on the axis with the amplitudes,
2) Order map; order and time (or RPM) on the axis with respective amplitudes.</p>
<p>... | https://dsp.stackexchange.com/questions/64228/frequency-and-order-maps |
Question: <p>I am a total newbie in signal processing.
I have been trying to plot on simulink a time/frequency domain noise in PLC (Powerline Communication) that matches a real-world research <a href="https://ieeexplore.ieee.org/abstract/document/5478758/" rel="nofollow noreferrer">"<code>Time Frequency Analysis of No... | https://dsp.stackexchange.com/questions/49778/plot-background-noise |
Question: <p>I have a problem with a FFT analysis in MATLAB, which is probably related to my limited understanding of the fundamentals of Fourier analysis. </p>
<ul>
<li>I use MATLAB’s built-in fft analysis function. </li>
<li>The sampling frequency is 48000Hz The samples signal is a fairly clean sinus at 3000Hz (se... | https://dsp.stackexchange.com/questions/15151/fft-analysis-of-longer-data-sets |
Question: <p>I'm new to frequency domain analysis. Let's say I have a frequency domain representation from a time domain signal. What I want to do is taking frequencies with a low amplitude out of this frequency domain representation and then convert this frequency domain representation back to the time domain such tha... | https://dsp.stackexchange.com/questions/30602/compressing-a-time-domain-signal-in-the-frequency-domain-matlab |
Question: <p>What are the Pros and Cons of using Wigner-Ville Distribution for spectral analysis of a signal vs taking the STFT. When is it appropriate to use one over the other and is WVD used in real-time implementations?</p>
<p><strong>Update:</strong> Since no answers were received for the first few days of this po... | https://dsp.stackexchange.com/questions/86211/wigner-ville-distribution-wvd-vs-stft-for-spectral-analysis |
Question: <p>I am analyzing some time series of sea surface water temperature and am using wavelet analysis to do so. I am computing the continuous wavelet transform and then removing some specific frequencies and then converting the series back from the frequency to the time domain. I am following the methods of torre... | https://dsp.stackexchange.com/questions/7822/wavelet-analysis-normalized-to-have-unit-energy |
Question: <p>I have been working with some seismic data and recently submitted a paper to a journal.</p>
<p>My seismic data has 493 traces: each trace are 8300 seconds long with sampling frequency of 2000 Hz.</p>
<p>One of the reviewers is asking me to generate a frequency spectrogram at the time= 2000s for all signa... | https://dsp.stackexchange.com/questions/53014/spectrogram-of-493-signals-at-a-time |
Question: <p>My inquiry is regarding the so called <a href="https://en.wikipedia.org/wiki/Cepstrum" rel="nofollow noreferrer">cepstrum</a> analysis.</p>
<p>By conducting some experiments, i have real time data at my disposal. The acquisition rate is 1600Hz.</p>
<p>I wanted to try cepstrum analysis just out of curiosi... | https://dsp.stackexchange.com/questions/38837/cepstrum-analysis-cut-off-frequencies-displayed |
Question: <p>A continuous time domain system is well described by the Laplace transform. It allows to express any continuous signal x(t) as the integral sum of weighted complex and exponentially growing/decaying sine waves <span class="math-container">$e^{st} = e^{\sigma t} \cdot e^{j\omega t}$</span>:</p>
<p><a href="... | https://dsp.stackexchange.com/questions/75831/why-is-z-and-not-%cf%89-the-variable-of-interest-for-discrete-time-systems |
Question: <p>I'm looking for a Fourier analysis method that will help me with a servo position tracking problem. I'll give some background:</p>
<p>Imagine I have a control system that attempts to control a linear actuator to a submicron position. I have a following error signal in units of nanometers that I monitor. In... | https://dsp.stackexchange.com/questions/96070/what-fourier-analysis-would-be-appropriate-for-analyzing-servo-position-error-as |
Question: <p>I have performed a cross-correlation analysis using <em>scipy.signal.correlate</em> to determine the phaseshift (time delay) between two sine waves that I have recorded with a 180MHz digitizer.
To increase the resolution of the time delay, I performed upsampling with different factors. I found a oscillatin... | https://dsp.stackexchange.com/questions/96192/converging-behaviour-with-upsampling-in-cross-correlation-analysis |
Question: <p>I am working on balancing an air-spindle. For the unbalance analysis I use an accelerometer (NI device). I have the voltage signal from the accelerometer corresponding to the vibration of spindle at a particular frequency (rpm) saved in an excel file. To analyze the unbalance from this vibration signal I u... | https://dsp.stackexchange.com/questions/40482/fft-analysis-for-vibration-signal |
Question: <p>I'm in the process of building features for an EEG machine learning problem and have been doing some reading about what features may be useful. Turns out, that alpha band (8-12Hz) power can make a good distinction between my categories. The nuance is that for 1 category, alpha power rises and then falls ov... | https://dsp.stackexchange.com/questions/25163/eeg-power-at-specific-time-points |
Question: <p>Hello friends am studying the topic of signal processing and the Fourier transform and the s-transform and in most books as for example "Time-Frequency Signal Analysis and Processing. 2nd" of Boashash in section 5.11.2.3 says that these transforms retain the absolute phase information of the signal and I d... | https://dsp.stackexchange.com/questions/29819/why-fourier-transform-and-stockwell-transform-retain-the-absolute-phase-informat |
Question: <p>I learned that the time constant can be computed as $\frac{1}{2 \pi f_0}$, where $f_0$ is the half-power cutoff frequency of a high-pass filter.</p>
<p>However, I was wondering how the time constant and the half-power cutoff frequency can be related. For example, if the half-power cutoff frequency is 2 Hz... | https://dsp.stackexchange.com/questions/51042/how-to-understand-the-relationship-between-the-filter-time-constant-and-the-half |
Question: <p>I am simulating a linear system described by the following equation</p>
<p>$m \ddot{x} + c \dot{x} + k x = A \sin(\omega t)$</p>
<pre><code>Fs = 1000; % sampling frequency
tspan = 0:1/Fs:10;
m = 25;
c = 15;
k = 330000;
A = 100; % forcing amplitude
omega = 114.89; % forcing frequency
% ... | https://dsp.stackexchange.com/questions/19779/system-response-time-vs-frequency-why-do-i-get-different-magnitudes |
Question: <p><a href="https://i.sstatic.net/OrSV8.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/OrSV8.png" alt="Sinc(10.t) Function and Amplitude Spectrum in the Frequency Domain" /></a>First of all, hello.</p>
<p>This question is about a problem that I’ve faced during an attempt to obtain both time an... | https://dsp.stackexchange.com/questions/73838/inconsistency-between-analysis-and-simulation-results-of-fourier-transform-of-a |
Question: <p>I have multiple trials of physiological data. I am doing a frequency based analysis to analyze power (amplitude) in certain frequencies of interest. Is averaging multiple trials of equal length and then taking a single FFT of the averaged signal vs computing FFT for each trial and then averaging the freque... | https://dsp.stackexchange.com/questions/7527/fft-time-domain-average-vs-frequency-bin-average |
Question: <p>David I.Shuman in "<a href="https://arxiv.org/abs/1307.5708" rel="nofollow noreferrer">vertex-frequency analysis on graph</a>" claims that,"we generalize one of the most important signal processing tools – windowed Fourier analysis – to the graph setting and When we apply this transform to a signal with fr... | https://dsp.stackexchange.com/questions/52000/generalized-translation-on-graph |
Question: <p>I wanted to do formant analysis using MATLAB and did everything according to the following tutorial:</p>
<p><a href="https://de.mathworks.com/help/signal/ug/formant-estimation-with-lpc-coefficients.html" rel="nofollow noreferrer">https://de.mathworks.com/help/signal/ug/formant-estimation-with-lpc-coefficie... | https://dsp.stackexchange.com/questions/71709/formant-analysis-lpc-matlab |
Question: <p>I am a student learning dsp. I like the subject. I could understand the discrete time signals. When I move into z transform. I could not understand it. </p>
<p>Z transform is the mapping from discrete signal to zplane to make frequency analysis easy. It would be great if users give some tips that could he... | https://dsp.stackexchange.com/questions/26774/the-right-way-to-approach-z-transform |
Question: <p>I'm trying to compute the highest frequency (as can be sampled) in some pretty manky looking discrete time-dependent signals. My current method - a discrete fourier analysis - fails for some pretty awful looking but clearly oscillating signals (with discernable highest frequencies).</p>
<p>My current meth... | https://dsp.stackexchange.com/questions/35028/find-highest-frequency-of-a-very-manky-signal |
Question: <p>I've read an article about "mains hum" forensics in <a href="http://hummingbirdclock.info/about" rel="nofollow noreferrer">http://hummingbirdclock.info/about</a> and about <a href="https://en.wikipedia.org/wiki/Electrical_network_frequency_analysis" rel="nofollow noreferrer">Electrical network fr... | https://dsp.stackexchange.com/questions/84852/how-do-i-distinguish-a-49-90-hz-sine-wave-from-a-49-95-hz-one-in-a-short-audio-r |
Question: <p>I have two questions regarding signal processing:</p>
<p>1) In my analysis I generate a signal in the time domain with a frequency of 0.1 Hz. I apply the FFT and then determine the peak frequency of the signal, which should be 0.1 Hz. But I notice that when I simulate my signal for 200s, the peak frequenc... | https://dsp.stackexchange.com/questions/15474/time-duration-of-a-signal-to-determine-the-peak-frequency |
Question: <h2>Background</h2>
<p>Here's the thing: using software for Finite Element Acoustic Simulation I got the dataset of frequency response from a room; software works by solving the wave equation in the interval $`[f_i,f_f]`$ so results come directly in the frequency domain and we save them into a .csv file:
<a ... | https://dsp.stackexchange.com/questions/50075/making-longer-a-time-domain-signal-by-adding-values-on-its-frequency-domain-wha |
Question: <p>How can I analyze a basic sine wave for its frequency phase and amplitude at a particular point in time in MATLAB? Are there any tools to do that? I am trying to do additive synthesis of inharmonic sounds in MATLAB, but having a great difficulty to extract the needed phase amplitude and frequency data of t... | https://dsp.stackexchange.com/questions/17142/how-can-i-analyze-a-basic-sine-wave-for-its-frequency-phase-and-amplitude-at-a-p |
Question: <p>I have an FRA (frequency response analysis) of a device that have magnitude and phase as shown in the following figure. Since the response is look different at different frequencies based on the operating point of the device under test, I want to extract the features from this response to further use for m... | https://dsp.stackexchange.com/questions/96473/feature-extraction-of-the-magnitude-and-phase-data-from-fra-frequency-response |
Question: <p><strong>Experiment:</strong> Vibration analysis (i.e.: major concern is on transfer function or frequency response).</p>
<p>The input is an impulse (imagine as a knocking effect or knocking force), defined as a half sine curve. The output is the vibration speed of the specimen (measured by laser vibrometer... | https://dsp.stackexchange.com/questions/72554/the-effect-of-time-increment-delta-t-frequency-resolution-delta-f-and-gib |
Question: <p>Let's say I have an audio sample, whose pitch is known to be C4 (don't wanna go in detail here, let's say I just sampled a tuned piano playing the C4 key).</p>
<p>The rules of the game are: I can only change the sample playback rate by any ratio. No pitchshifter module, no frequency analysis. If I set the... | https://dsp.stackexchange.com/questions/7721/pitch-vs-playback-rate |
Question: <p>This is a cross posting from the crossvalidated stack exchange as I thought this may be a better forum to ask.</p>
<p>I have a dataset consisting of respiratory time series signals of different lengths obtained from different groups of patients. I want to either classify or cluster the patients using these... | https://dsp.stackexchange.com/questions/71917/help-with-denoising-signal-and-periodogram-analysis-resources |
Question: <p>I have two time-domain signals sampled at 100 Hz that were measured using two different oscillators and therefore have a time drift between them. I have two synchronization points, one at the start and one at the end of the measurement (usually about 24h long).</p>
<p>The drift is very small, about 1 seco... | https://dsp.stackexchange.com/questions/53246/matching-two-signals-with-small-time-drift |
Question: <p>I'm trying to get an intuitive understanding of the different coefficients in detrended fluctuation analysis (DFA).</p>
<p>It is used to detect fractal patterns in time series and it yields a coefficient, Alpha, which, as I understand is a Hurst coefficient mapped for different scales — the slope of which ... | https://dsp.stackexchange.com/questions/72512/why-does-alpha-of-0-5-in-detrended-fluctuation-analysis-indicate-randomness |
Question: <p>I'm attempting to perform multi-resolution analysis via Continuous-Wavelet Transform (CWT) using Pywavelets. I've heard that CWT is supposed to be superior to STFT due to varying frequency content as a function of the time-window.</p>
<p>My test signal is two sinusoids of 1Hz and 5Hz, each lasting 10 secon... | https://dsp.stackexchange.com/questions/58939/cwt-disapointing-frequency-separation |
Question: <p>Since a couple of months I started working on the extraction (estimation) of signal frequency and amplitude components by means of two different time-frequency approaches, namely the Hilbert transform and the Teager-Kaiser energy operator.</p>
<p>I tested both methods on standard signals, such as chirps, ... | https://dsp.stackexchange.com/questions/21662/teager-kaiser-operator-vs-hilbert-transform |
Question: <p>I am not sure if I am missing something, but from what I read I understand that modern control systems work in the time domain rather than the frequency frequency or S-domain.</p>
<p>Wikipedia article snapshot below:</p>
<p><a href="https://i.sstatic.net/mXuF3.png" rel="nofollow noreferrer"><img src="https... | https://dsp.stackexchange.com/questions/75281/why-is-modern-control-theory-in-the-time-domain-instead-of-the-s-domain |
Question: <p>I have just started taking signal & systems lessons and here is my question:</p>
<p>If we say that <code>x0(t) = A.cos(w0t)</code>. (<em>a cosine signal with zero phase shift, w0 radian frequency)</em> And if we would like to time-shift this signal by for example <code>t1</code>.</p>
<p>The resulting... | https://dsp.stackexchange.com/questions/50461/converting-time-shift-to-phase-shift |
Question: <p>I'm reading about when a <span class="math-container">$H(z)$</span> system is min phase or max phase, and I get when a system is a min phase or max phase depending on the location of the zeroes. But I don't get at all the phase shift part. on one point wikipedia says that these two transfer functions:</p>
... | https://dsp.stackexchange.com/questions/75064/what-is-phase-shift |
Question: <p>I heard that an IIR filter has delay and phase shift effect, but not clearly what are they. For example, 1-pole Lowpass has 90 degree phase shift, 2-pole Lowpass has 180 degree? So does it mean two 2-pole Lowpass filters has 360 degree phase shift? Beside the HighPass, LowPass, AllPass filter, other IIR fi... | https://dsp.stackexchange.com/questions/24317/iir-filter-and-phase-shift |
Question: <p>I'm trying to apply a frequency shift to a generated despreading code in order to find and track a broadcast signal CDMA. Expected doppler shift range of the signal from center frequency would be approx +/- 5KHz. Based on freq2 = c/(c-orbitspeed) * freq1.</p>
<p>I am wanting to shift the code based on equa... | https://dsp.stackexchange.com/questions/13841/frequency-shift-and-phase-shift-doppler |
Question: <p>Suppose I have a sine wave <span class="math-container">$u(t) = \sin(2\pi f t + \phi)$</span> of known frequency but unknown phase shift and I want to find the phase shift. One way of doing this is multiply-and-adding <span class="math-container">$u(t)$</span> by a <span class="math-container">$\cos(2\pi f... | https://dsp.stackexchange.com/questions/83101/finding-phase-shift-using-complex-exponential |
Question: <p>I'm seeking a good advice for a filter. Can you help me?</p>
<p>Right now I made my own simple filter. Not sure what I'm doing, but it seems to work.</p>
<pre><code>function testFilter (t, y, p)
% Forward filtering
% Do first filtering by jumping k/2 elements in the future
l = length(t);
ye ... | https://dsp.stackexchange.com/questions/66617/a-filter-with-low-phase-shift-or-no-phase-shift-at-all-which-one |
Question: <p>So I got some oscilloscope captures for a project I'm doing and I'd like to find a phase shift between them because I don't trust the scope calculation. </p>
<p>So I extracted data from a .csv file and loaded it into Matlab and now I'd like to find a phase shift using FFT (I think). Is there a way to do t... | https://dsp.stackexchange.com/questions/33485/phase-shift-between-two-signals |
Question: <p>Fred, a DSP engineer, goes to his favorite DSP store to do some shopping.</p>
<p><strong>Fred:</strong> Hi, I'd like to buy a phase shifter.</p>
<p><strong>Shop assistant:</strong> Hmm, what exactly do you mean?</p>
<p><strong>Fred:</strong> Well, you know, if you put in a sinusoid like $x(t)=\sin(\omeg... | https://dsp.stackexchange.com/questions/31597/how-to-build-a-phase-shifter-with-arbitrary-phase-shift |
Question: <p>What is the difference between Digital phase modulation(DPM) and Phase shift keying (PSK)? <a href="http://suraj.lums.edu.pk/zartash/publications/2007-DigitalPhaseMod.pdf" rel="nofollow noreferrer">http://suraj.lums.edu.pk/zartash/publications/2007-DigitalPhaseMod.pdf</a> It says that PSK is a special case... | https://dsp.stackexchange.com/questions/41039/confusion-in-phase-shift-keying |
Question: <p>To help demonstrate why a time delay appears as a linear phase shift and not a constant phase shift I wanted to plot what a constant phase shift looks like.</p>
<p>I have been looking at the Hilbert transform, which shifts the phase (of positive frequencies) by <span class="math-container">$-90^\circ$</sp... | https://dsp.stackexchange.com/questions/59270/how-to-achieve-an-arbitrary-phase-shift |
Question: <p>I would like to apply a phase shift by multiplying by a complex exponential in Fourier space, then taking the inverse transform. I've almost got it, but it's a factor of 2 off. I want the phase shift to be <span class="math-container">$\pi/4$</span>, but it's showing a shift of <span class="math-container"... | https://dsp.stackexchange.com/questions/95727/apply-phase-shift-using-fft-and-complex-exponential |
Question: <p>I have read some literatures about the different topologies of beamforming and it came to my mind a question : where is applied the phase shift for each channel depending on the type of topology/technology used?</p>
<p>For analog beamforming, it is obvious as there is only one signal, the modulated carrie... | https://dsp.stackexchange.com/questions/64093/digital-beamforming-and-phase-shift-stage-insertion |
Question: <p>I am researching a dynamic system. It takes in a sine wave <code>A*sin(2*pi*f*t) + D</code> and outputs a non-isosceles triangle wave. Let's call input signal SP and output signal PV. I want to create amplitude and phase characteristics of this system. I have taken measurements of SP and PV for different <... | https://dsp.stackexchange.com/questions/91541/phase-shift-of-non-isosceles-triangle-wave |
Question: <p>I'm trying to find the phase shift between two 100x100 matrices, s and p. To start with I'm using two sine waves (2D) slightly shifted. I manage to compute the correct amplitude spectrum (using the Fourier Transform of the cross correlation between s and p) but the phase value at the peaks is not the one t... | https://dsp.stackexchange.com/questions/24611/phase-shift-between-two-images-matrices |
Question: <p>I try to make graph/print for magnitudes and phase shifts for impulse response calculated by FFT.
For magnitude everything works perfect, but for phase shift I get some strange curve for higher frequencies. I can't figure out why. Could anyone help me?</p>
<p>I calculate phase shift by that:
<code>atan2(f... | https://dsp.stackexchange.com/questions/51841/phase-shift-problem-in-fast-fourier-transform |
Question: <p>I want to shift the response phase of an audio signal (float array, length N, value range -1..1). I'm about using Fast Hartley Transform to transform it to the frequency-domain, process phase shift, then convert back to the time-domain and output the result.<br/>
I'm now can do the Hartley transform, and I... | https://dsp.stackexchange.com/questions/24357/audio-phase-shift-using-hartley-transform |
Question: <p>In MATLAB's Comm System Toolbox there is an option for 'Phase Rotation', defined as the phase difference between previous and current modulated symbols when the input is zero. This is the first time I've heard of this concept. </p>
<p>Let's take DQPSK as an example. Say my previous symbol had an absolute ... | https://dsp.stackexchange.com/questions/30252/reasoning-behind-additional-phase-shift-in-dpsk |
Question: <p>The most common type of discrete cosine transform (DCT-II) is defined as
<span class="math-container">\begin{align}
X_k&=\sum_{n=0}^{N-1}x_n\cdot \cos\left(\frac{\pi}{N}\left(n+\frac{1}{2}\right)\cdot k\right)&\text{where }& k=0,1,...,N-1
\end{align}</span>
(c. f. <a href="https://en.wikipedia.... | https://dsp.stackexchange.com/questions/72892/phase-shift-of-discrete-cosine-transform-dct |
Question: <p>I'm not a specialist in this field and learnt FFT fairly recently.</p>
<p>I want to calculate phase difference of between 1 MHz signals sampled at 4 MHz. The sample counts are both 144. I think the magnitudes and the frequencies are all correct. But phase shifts are off.</p>
<p>So, I decided to go back and... | https://dsp.stackexchange.com/questions/88501/calculate-phase-shift-using-fft |
Question: <p>I was learning Modulation Techniques and was on the topic Phase Shift Keying (PSK). As far as I have understood, </p>
<p>In Binary PSK we encode a single bit on a one signal element and we differentiate between two bits (or two signal elements) by their different phase. And that it's favorable to keep th... | https://dsp.stackexchange.com/questions/60902/binary-and-quadrature-phase-shift-keying |
Question: <p>When I have digital audio signal, represented in samples, I can easily phase-shift the signal by 180° by simply inverting the value of each sample.</p>
<p>But what if I want to phase shift an arbitrary voice audio signal by say +90° or -90°?</p>
<p>How do I transform an arbitrary, discrete signal by phas... | https://dsp.stackexchange.com/questions/48976/how-to-calculate-arbitrary-phase-shift-in-discrete-signal |
Question: <p>This is probably a really basic question but I'm a little stumped and would appreciate some practical input on how to go about doing this rather than reading dockets of equations semi-related to what I am doing. </p>
<p>So say I have data which is largely reminiscent of a sine wave. I do an forward Fourie... | https://dsp.stackexchange.com/questions/23655/sine-wave-phase-shift-from-fourier-transform |
Question: <p>I designed an FIR highpass filter which is causing a phase shift to the output. The output signal is also not stable (?) on start.
Are these normal or am I doing something wrong?
If these are normal, what causes these?
(Attached is a diagram showing the input in blue and the output in red).<img src="https... | https://dsp.stackexchange.com/questions/23369/fir-filter-phase-shift-and-stability |
Question: <p>I know about <a href="http://whatis.techtarget.com/definition/phase" rel="nofollow">phase of a 1D signal</a>. But when I go into higher dimensions like 2D,3D etc, it becomes headache to grasp the concept. </p>
<ul>
<li>What are the terms phase shift and phase spectrum mean in case of multidimensional(2D,3... | https://dsp.stackexchange.com/questions/22711/phase-shift-and-phase-spectrum-terms-in-multidimensional-signal |
Question: <p>While going through FFT I came to know that, shifting of phase in frequency domain results on shifting of time in time domain.</p>
<p>According to this, in wireless communications, from the transmitter side having 2 antennas,signal s1 transmitted from Ant 1 and phase shifted version of sig2 in frequency d... | https://dsp.stackexchange.com/questions/9154/frequency-domain-phase-shift |
Question: <p>I have ECG signal sampled at 100Hz & using Python to remove noise, and generate a template signal from the collection of ECG from a total of almost 4700 signals. I have removed the noise from ECG using PCA and now looking to 'stack' together signals on top of each other to generate a template signal wh... | https://dsp.stackexchange.com/questions/89069/removing-phase-shift-in-ecg-signal |
Question: <p>I have two signals with nearly the same frequency, and i would like to find the phase shift between them, since i am using micro-controller, i would like to do it in the less expensive way.</p>
<p>I know how to calculate Goertzel for a specific frequency bin (for each signal), but how do i calculate the a... | https://dsp.stackexchange.com/questions/23944/using-goertzel-to-find-phase-shift |
Question: <p>Consider the measurements of two modulated AC signals (voltage and current) which may have noise, harmonics and a DC bias. Each measured signal consists of a list for the time and a list for the corresponding values.</p>
<p>My goal is to find out the phase shift in degrees between these two signals in a r... | https://dsp.stackexchange.com/questions/10723/calculate-phase-shift-between-two-signals |
Question: <p>I red that 180 degree phase shift causes spurious high frequency components which As a result methods such as OQPSK are invented, but I can't understand how it can happens? In fact, I can't find any connection between 180 degree phase shift and the creation of high frequency components. or for example why... | https://dsp.stackexchange.com/questions/93604/whats-wrong-with-180-degree-phase-shift-in-qpsk |
Question: <p>What are Method to phase shift 50 Hz digital signal using microcontroller. Appart from storage of samples to array and shift sample wise,how to shift this signal fractionally.</p>
Answer: <p>You do it by creating a windowed sinc filter that has a wide enough pass-band to preserve the energy of whatever it... | https://dsp.stackexchange.com/questions/4709/phase-shifting-of-50hz-signal |
Question: <p>I am aware of the fact that a time shift of say <span class="math-container">$t_0$</span>, results in a phase shift in the frequency spectrum. What confuses me is how this scales the rotational part of the transform by <span class="math-container">$t_0$</span> and doesn’t add a factor of <span class="math-... | https://dsp.stackexchange.com/questions/65891/how-does-a-shift-in-time-domain-result-in-phase-shift-in-frequency-spectrum |
Question: <p>I'm using Octave and trying to use the "instfreq" function from the <a href="http://tftb.nongnu.org/" rel="nofollow">time frequency toolbox</a> which requires an analytic signal input. To get this analytic signal I'm using the Octave function "hilbert" on my real valued signal thus:</p>
<pre><code>analyti... | https://dsp.stackexchange.com/questions/16507/compensate-for-phase-shift-of-hilbert-transform |
Question: <p>I was wondering if there is something like a Hilbert Transform but that can implement an arbitrary phase shift to every frequency component.</p>
<p>I mean, I know that the magnitude response of a "Hilbert filter" is 1 for all frequencies and the phase response is <span class="math-container">$-\p... | https://dsp.stackexchange.com/questions/72009/something-like-hilbert-transform-to-obtain-arbitrary-phase-shift |
Question: <p>I have an incoming digitally sampled sine wave pulse, so my FPGA has the ADC level from an I and Q channel. I want to be able to shift the phase by some arbitrary amount. </p>
<ul>
<li>What's the most efficient way to do this?</li>
</ul>
<p>The most obvious way to shift phase would be just to multiply by... | https://dsp.stackexchange.com/questions/31226/best-way-to-implement-variable-phase-shift-on-fpga |
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