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Star Strider


12,413 total contributions since 2012

Hic sunt dracones!

PROFESSIONAL: Physician (M.D.): Diplomate of the American Board of Internal Medicine; M.Sc. Biomedical Engineering: Instrumentation, Signal Processing, Control, System Identification, Parameter Estimation

NON-PROFESSIONAL: Amateur Extra Class Amateur Radio Operator; Private Pilot, Airplane Single Engine Land, Instrument Rating Airplane; Gamer

NOTE: I do not respond to emails or personal messages, unless they are about my File Exchange contributions.

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Answered
How to do a nonlinear fit using least squares
This is actually a linear problem, so a linear approximation will estimate the parameters correctly: R = 8.314462; ...

11 hours ago | 1

| accepted

Answered
Finding matrix values associated with plot point
One approach: A = rand(10,2); A(4,:) = [75 0.995]; Lrow = ismembertol(A, [75 0.995], 0.01, 'ByRows',1) RowNr = find(Lrow)...

12 hours ago | 0

Answered
Unable to save data or continue through loop
I can’t run your code. However, since you are not defining the character array ‘Filenamesave’ as a cell array earlier in your c...

14 hours ago | 0

Answered
Can get the low pass filter to filter the data properly
It is difficult to determine what the problem is without knowing more about the signals. A FIR filter (exspecially a long FIR f...

16 hours ago | 0

Answered
Calculate slope at specific time over many days using polyfit and for loop
You appear to be calculating them correctly, just not storing them correctly. For a linear fit, polyfit will produce a (1x2) ve...

16 hours ago | 0

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Answered
How can I create a legend on the interception of 2 lines on a plot with its coordinates?
I demonstrated how to do that in: How can I interpolate a point in a x,y graph given only one of these values and being the poin...

17 hours ago | 0

Answered
unable to use Low pass filter on experimental data
When I substitute some vectors for the missing data, the posted code runs for me without error. The filter function should ta...

19 hours ago | 0

| accepted

Answered
Isolating a single pulse by removing noise
Try this: A = dlmread('F0000CH1.csv',",",0,3); Time = 1e9.*A(:,1); Voltage = A(:,2); figure plot(Time,Voltage,'LineWidth...

1 day ago | 1

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Answered
How to change the time increment of a text file to make a new data set from an existing one?
Use interp1: A = [1.1 7 8 5 1.2 8 9 4 1.3 9 10 3 1.4 10 11 12 1.5 11 12 1]; NewCol1 = min(A(:,1)) :...

1 day ago | 0

Answered
Grid of values spacing in logarithmic scale
I am not certain what you want. Try this: xv = logspace(-5, -1, 25); yv = linspace(0, 1, numel(xv)); figure semilogx(x...

2 days ago | 0

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Answered
How do I solve the inverse kinematics of a nonlinear differential equation?
You can use the techniques in: Parameter Estimation for a System of Differential Equations. You can likely optimise with respec...

2 days ago | 0

Answered
I have a *.wav file. How do I change the bit rate(bits per sample) of it?
The only way I am aware of to change the bit rate is to read the audio file using audioread, then write it with audiowrite using...

2 days ago | 0

| accepted

Answered
How can I graph exponential functions?
First, do not use the exponentiation operator here: y1 = (2*exp(-2*t)-7*exp(-2*t)+0.6)/(4*exp^(-2*t)); ...

2 days ago | 0

Answered
Plot 2D points in 3D space
Since your trajectory is defined by two vectors, if you want to plot it in 3D space, you need to provide another vector. The ea...

3 days ago | 0

Answered
How can I interpolate a point in a x,y graph given only one of these values and being the point on the line?
Try this: x = 1:10; y = rand(1,10); figure plot(x,y) hold on xl = xlim; plot(xl(:)*[1 1], [1;1]*[0.5 0.9], '--r') hol...

3 days ago | 0

Answered
plotting data from data files and saving each plot through out each run of the loop
You are likely seeing only the plot of the last file read. It is likely best to do the fiie reading and plotting in separate ...

3 days ago | 0

Answered
How to get period and frequency components of a signal?
A one-sided Fourier transform is a bit easier to interpret: % Ex 1B % Load the file load("xp.dat"); f_s = 8192; %sample f...

3 days ago | 0

Answered
Error: Index in position 1 is invalid. Array indices must be positive integers or logical values.
The problem is that ‘i’ and ‘j’ are initially both 0. I also did what I could to speed up your code, although it is still ext...

3 days ago | 1

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Answered
Entering state space model into matlab and using ode45 for non-linear thrust force
You willl need to write a function file for your system. See Function Basics for details. For the input, see the ode45 docum...

3 days ago | 0

Answered
Array indices must be positive integers or logical values.
The code you posted runs for me without error. What line is throwing the error when you run it?

3 days ago | 1

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Answered
Convert 99 1x6 to six 1x99 vectors
Concatenate them vertically to get a (99x6) matrix, then transpose the matrix.

3 days ago | 0

Answered
Designing a differentiator filter using cfirpm
The moving average filter is easy enough to design: Fs = 250; % Sampling Frequency (Hz) ...

4 days ago | 0

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Answered
Display time on x axis
It depends on what options you have. For datetime arrays, see Plot Dates and Durations. If you are using datenum date numb...

4 days ago | 0

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Answered
getting the max and its positions from a 4D array
Try this: A = rand(3,3,3,3); % Create Array Amax = max(A(:)); ...

4 days ago | 2

Answered
How to normalize two waves on a single plot
Try this: t=0:0.001:0.05; y= 11.18*cos(60*pi*t+26.565); y2= -60*pi*11.18*sin(60*pi*t+26.565); title('Phasor Waveforms') ...

4 days ago | 1

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Answered
How can I combine multiple wav files into a single new wav file
Use audioread to read them, then vertically concatenate them (assuming they all have the same numbers of channels=columns) using...

5 days ago | 0

Answered
how to plot empirical cdf in matlab release 2013a
One approach: x = randn(100,1); % Create Data binrng = linspace(-5, 5, 26); ...

5 days ago | 0

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Answered
finding real roots of polynomials
With only symbolic variables, it is not possible to determine if any of the roots are complex, unless one or more of the variabl...

5 days ago | 0

Answered
How to calculate the rate using a given data set?
You are not coding your differential equations and data correctly. See for example: Parameter Estimation for a System of Differ...

5 days ago | 0

Answered
convert time to frequency domain
To normalise it to a maximum value of 1, divide the Fourier transformed data by the maximum of the Fourier transformed data: D...

5 days ago | 0

| accepted

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