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Star Strider


Last seen: Today Active 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. Time Zone: UTC-7 (Standard); UTC-6 (Daylight Savings/Summer)

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Answered
Understanding this FFT Graph
‘My question is; what would the label be for the Y-axis and secondly, is the X axis just frequency in the time domain?’ The Y...

12 hours ago | 0

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Answered
FFT Analysis of Sine Sweep
Your posted code is likely as good as it is possible to get. I added a pspectrum call at the end — T=5; %size of window fs...

17 hours ago | 0

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Answered
Time response of modes to an impulse
If I understand correctly what you want, it is possible to return the state trajectories with lsim as described in Extract Simul...

19 hours ago | 0

Answered
Error with the SIR Model
I cannot run this since my version of MATLAB only allows me to run actual code, not images of code. (Maybe that will be fixed i...

1 day ago | 0

Answered
Reading complicated CSV file
Try something like this — C1 = readcell('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1007390/random.csv'); ...

1 day ago | 1

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Answered
How to solve a nonlinear system with 6 equations but with only 4 variables?
Use the mldivide, \ operator to do a least-squares determineation of the system. See the documentation for details. .

2 days ago | 0

Answered
Problem with cycle within a cycle output
If I understand correctly what you want to do, in every ‘j’ iteration, ‘h’ needs to be reinitialised, so: h = 1; whil...

2 days ago | 0

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Answered
Precise Prediction Model Development
What are you predicting? How does ‘y’ fit in with this? Is it a separate vector? With those concerns met, building the ...

2 days ago | 0

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Answered
How to filter noise in EMG signal - Tibialis anterior muscles
First, before calculating the fft, subtract the mean of the signal to eliminate the D-C (0 Hz) spike so the other peaks are more...

2 days ago | 0

Answered
How to match the rising starting point of the graph
This is my best effort. I could not get the other functions I tried (ischange, findchangepts, islocalmin, etc.) to work, so I w...

3 days ago | 2

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Answered
I exported data from excel into a table, how do I sum the values of each column from that table excluding NaN's
Two options — T = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1005700/Inventory.xlsx') S1 = nan...

4 days ago | 0

Answered
How to overcome the problem with the function diff used to approximate matrix derivative.
Use the gradient function instead of diff.

4 days ago | 0

Answered
How to interpolate a column array based on another non-linearly spaced column array?
As a general rule, it is best to interpolate a longer vector to a shorter vector in order to avoid creating data that interpolat...

4 days ago | 0

Answered
Incorrect use of '=' operator for an IF statement
I usually do something like this in setting an index range — L = numel(Componentry_New) for k = 1:Whatever Level_Either_...

4 days ago | 0

Answered
Trying to learn how to add a threshold trigger and peak markers.
Try something like this — x = linspace(0,10,500); red_line = sin(2*pi*x)*1.5; trigger = find(diff(sign(red_line - 0.95)));...

4 days ago | 0

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Answered
What does this Digital filter actually do? and what is it called?
It is a 2D FIR filter: I am not certain it has any other name. To see what it does, plot its results — H = [1 1 1 1 1;1 2...

5 days ago | 0

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Answered
How to add date and time in a plot by command in matlab 2012?
I no longer have access to R2012a, so I cannot test this with it. The code you posted works correctly in R2022a, however R201...

5 days ago | 0

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Answered
Three columns (x,y,z) in table, Loop through table for each X plot Y vs Z
Try this — CA = {'A' 1 3 'A' 2 4 'A' 3 10 'B' 1 4 'B' 2 4 'B' 4 6 'C' 0 1 'C' 1 4 ...

5 days ago | 0

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Answered
How to implement a for loop on figure plotting?
Try something like this f = 1:500; Q = randn(115,500); idx = 1:100; % Choose Specific Columns fi...

5 days ago | 0

Answered
I want to find the area of the graph
Try this — LD = load('x,y.mat'); x = LD.xy(1,:); y = LD.xy(2,:); yf = sgolayfilt(y, 3, 1001); ...

5 days ago | 1

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Answered
Can "datetime" be responsible for the misalignment of data in a plot ?
The first cluster of data (at about 2.5 or about 18 Jun) appears to be perfectly aligned in both plots. The datetime plot goes...

6 days ago | 1

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Answered
How can I add uncertainty to a data matrix?
The repmat funciton is likely not needed. Just do something like this: h = h + randn(size(h)); and so for the rest. See t...

6 days ago | 0

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Answered
ERROR: Array indices must be positive integers or logical values. Can anyone please help, Thank You!
I suspect the problem is with this term — u(u*UmaxN_0+PsByN_0*u) and everywhere else something similar to that is used. The ...

6 days ago | 0

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Answered
Why doesn't my state-space model iterate?
The iterations are defined inside the function. See the documentation section on Display to see the progress of the estimation....

6 days ago | 0

Answered
How to FFT my xlsx files from time domain to frequency domain?
Try this — T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1000730/delay%2040ms%20speed%20100%2...

7 days ago | 0

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Answered
Extend a cell array of dates (from days only, to hours and days) in a compact way
Try this — C1 = {'17-Jun-2017'; '30-Jul-2017'} DT1 = [datetime(C1{1}) : days(1) : datetime(C1{end})]' DT2 = [min(DT1): hou...

7 days ago | 1

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Answered
How to utilize 'symsum' in this case?
Try something like this — syms i j t Y Eq = symsum(Y,j,2,5) * (symsum(t,i,1,j)^2 - symsum(t,i,1,j-1)^2) .

7 days ago | 0

Answered
I am trying to find the integral gain (ki) of the following transfer function.
Symbolic variables are not permitted in Control System Toolbox objects, however anonymous functions are. Try this — sys = @...

7 days ago | 0

Answered
Scatterplot with two x and y axes only showing one dataset
The code only creates one tile: t = tiledlayout(1,1); Changing it to: t = tiledlayout(1,2); or: t = tiledlayout(2,1); a...

8 days ago | 0

Answered
How to solve third order equation using ode45
I let the Symbolic Math Toolbox do everything — syms y(t) T Y Dy = diff(y); D2y = diff(Dy); D3y = diff(D2y); Eq = D3y - D...

8 days ago | 1

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