# Greg Dionne

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**Feeds**

How is the number of sample points returned by waypointTrajectory determined?

It's hard to say for certain without trying your specific value for the sample rate, fs, and desired ending time, tEnd, but off-...

2 years ago | 0

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Average of a each vertical section of a stepped sawtooth wave

If you have the Signal Processing Toolbox, FINDCHANGEPTS is worth a look (it will give you the indices of each step of which you...

3 years ago | 1

changing color of structure which defined as object

The platformPlotter is intended to plot (possibly multiple) objects at once with a unique color. The orientationPlotter is in...

3 years ago | 1

| accepted

How to edit original data in for-each equivalent statement

You can often avoid the need for references and the for-loop altogether in MATLAB. This example should get you started: classd...

4 years ago | 0

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Segmentation of audio signal.

If you have the Signal Processing Toolbox, buffer may be what you're after. Hope this helps! -Greg

5 years ago | 0

RMS Function Returns NAN

It's likely you have NaN in your input, or your input is an empty vector. If you wish to exclude NaN values from computation, t...

5 years ago | 0

| accepted

thd() in matlab workspace shows me an unexpected result, is anything wrong ?

The default window used when running the THD function has a wide rolloff which masks the second and third harmonics in your sign...

5 years ago | 2

| accepted

Why this bandpass butterworth is unstable (while the corresponding low and high pass are stable)?

You will have better results if you use second-order sections. See the "Limitations" section of https://www.mathworks.com/help/...

5 years ago | 2

| accepted

medfreq with delta-F threshold ?

From what I can tell your sinusoid is around ~895 Hz and has fairly clean second and third harmonics. So I took that as the sta...

5 years ago | 0

| accepted

measure time from fft spectrogram

You can extract the time vector from the third output of the spectrogram function. [S,F,T,Pxx] = spectrogram(X,...) F is the...

5 years ago | 1

| accepted

Fast Fourier Transform of the subtraction between a signal and the same signal but shifted

Circularly shifting in the time domain is equivalent to multiplying by a phase ramp in the frequency domain. The FFT of the va...

5 years ago | 1

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How to get pairwise distance matrices from dynamic time warping dtw on a matrix of time series ?

Your signals look extremely well time-aligned (within a sample). Since you have NaN, I suppose you could just perform a weigh...

5 years ago | 0

Warping window in "findsignal()" for dtw as TimeAlignment.

At the moment there are no warping constraints used in the FINDSIGNAL variant of DTW. I'm usually successful at coaxing it to...

5 years ago | 0

FFT of Downsampled Signal

Hi Adam, If you have significant noise on the signal, then decimate(x,10) or resample(x,1,10) would be preferable. Your result...

5 years ago | 1

| accepted

Making a video showing trajectories of particles

This should get you started: load Trajectories.mat hAxes = newplot; colors = lines(10); axis(hAxes,[0 1300 0 1100]) f...

5 years ago | 0

| accepted

DSP TOOL BOX NOT WORKING Spectrum Analyzer For Two-Sided Power Spectrum

This worked for me: sin = dsp.SineWave('Frequency',100,'SampleRate',1000); sin.SamplesPerFrame = 1000; scope = dsp.SpectrumAn...

5 years ago | 1

| accepted

Generating a sound that goes up and down in frequency - based on a vector of numbers

Hi Harriet, I'm glad you have the Signal Processing Toolbox and were successfully able to use vco, resample, and spectrogram to...

5 years ago | 0

Weighted spline for calculating trajectory with lowest possible lateral acceleration

I'm not certain if I understood your question correctly, but you could try adapting the approach in the drivingScenario trajecto...

5 years ago | 0

How to select matching records based on the differences in their detection time?

I think you want something like this(?): function [t1s, t2s] = szanto(t1, t2) % compute time vectors offset from first tim...

5 years ago | 0

How to find the slope of phase data (between two points) which is uneven

You could try a combination of <https://www.mathworks.com/help/matlab/ref/unwrap.html unwrap> (to remove the jumps of your array...

5 years ago | 0

Looking for a way to patch 44k polygons fast

Have you tried using just one patch? You can specify X and Y as matrices (this example taken from the doc page on <https://www....

5 years ago | 0

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how to apply dynamic time wrapping

DTW(X,Y) can work on vectors of non-equal length. It will repeat elements in either X or Y so that the comparison is of the sam...

5 years ago | 0

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How can I determine the diameter (inner and outer) of the ring profile?

Try this link: <https://www.mathworks.com/help/images/detect-and-measure-circular-objects-in-an-image.html>

6 years ago | 0

Why does findchangepts doesn't work right?

If you have R2016b or later try: Fs = 100; [sst,f] = fsst(Ch9,Fs,kaiser(512,10)); fridge = tfridge(sst,f,10,'NumRidge...

6 years ago | 1

Time response of the voltage

Most of the documentation for the bilevel measurements panel can be found here: <https://www.mathworks.com/help/simulink/ug/bile...

6 years ago | 0

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ismember runs too slow (others have asked similar questions)

Looks like your positional data could fit in a 3-D histogram (168x24x168). This could be made considerably faster, but hopefull...

6 years ago | 1

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plot a smooth envelope for oscillation curves

Do you have a particular selection criteria for the peaks or formula for how you would like the smoothing performed at the ext...

6 years ago | 0

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How to combine Matlab's build-in functions dtw and pdist?

You'll want to take the output of DTW and put it into a form that PDIST can recognize. This should get you started: func...

6 years ago | 1

Filter big data simulink or matlab

<https://www.mathworks.com/help/signal/ref/hampel.html hampel> should get you started plot(hampel(OutAIS.Data)) If you n...

6 years ago | 1

| accepted

colthoid fitting using trajectory();

The trajectory generator uses a fast discrete solver to obtain a G2-continuous path, so some discontinuities (usu < 1 degree/met...

6 years ago | 0