Community Profile # 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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How to find the frequency and amplitude of an oscillating signal?
One approach — T1 = readtable('book1.xlsx', 'VariableNamingRule','preserve') VN = T1.Properties.VariableNames; t = T1{:,1}; ...

2 hours ago | 0

Problem with hanning window
The window functions correct for the fft being finite, when the Fourier transform has infinite support (goes from ). The wind...

5 hours ago | 0

How can I solve this datetick error?
The datetick function uses MATLAB datenum values to calculate and plot the dates and times. A much simpler approach uis to us...

6 hours ago | 0

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Using fit, which coefficients should I extract to assess differences?
Only ‘c’ and ‘d’ are signifiantly different from zero, since the confidence limits of ‘a’ and ‘b’ include zero (the confidence l...

1 day ago | 0

How to plot a vector for fixed intervals
One approach — t = sort(rand(1,4)); tv = [t(1) t(2) t(3) t(4)] a = rand(1,3); A=[a(1) a(2) a(3)] figure plot([tv(1:3); ...

1 day ago | 0

How the increase the affect of lowpass filter on a field data?
The cutoff frequency of the lowpass filter is too high. Try these — LD = load('T35.mat'); T35 = LD.T35; sampling_interval...

1 day ago | 0

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Adding Contour Lines to a 2D Surf Plot
Use the contour3 function (with the hold function) — [A,B,C] = peaks(50); figure(13) surf(A,B,C) hold on contour3(A,B,C...

1 day ago | 1

Interpolation of inaccurate datapoints
If you want to approximate the data with a smooth curve and do not want it to go through all the data, one option for a 2D probl...

1 day ago | 0

How can I use various colors to fill the area under a normal distribution curve?
Sure! Try this — x = linspace(1.5, 5, 250); mu = 3.3; s = 0.6; y = normpdf(x, mu, s); figure plot(x, y) hold on Lv...

1 day ago | 1

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problem of using findpeaks
My guess is that the datetime values are not considered to be monotonically increasing because they span multiple years. Try ...

1 day ago | 1

How to find roots of a quartic function with unknown constant coefficients?
One option to explore its properties is to use the fimplicit function — f = @(x,a) x.^4 + 10.1*a.*x.^3 + 1.81*x.^2 + 9*a.*x + ...

2 days ago | 0

how to open .fdt file
Searching the Interweb (with DuckDuckGo), I found 15.1 How to load EEGLAB .set and .fdt files without using EEGLAB (05/09/2020 u...

2 days ago | 1

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How to find duration of peaks/valleys in chart
Try this — T1 = readtable('NV1-9999.csv', 'VariableNamingRule','preserve') VN = T1.Properties.VariableNames; x = T1{:,1}; ...

2 days ago | 1

What is the function to use to blacken a region?
Perhaps this — % clear %% Plotting the graphs % We have p(x) = 16 => p(x) - 16 = 0 f = @(x) (800000 .* exp(-x./5000)) ./ (x...

4 days ago | 0

Code of Highpass filter for objective function in pso algorithm.
In filter design, lowpass filters are the prototype. Transform it to a highpass filter with the Signal Processing Toolbox lp2...

5 days ago | 0

why is this not outputting the correct values
There is a syntax error, in that you used a colon operator ‘:’ instead of a comma in the ‘pythtrips’ references. The syntax is ...

5 days ago | 0

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Creating an equation with 2 unknowns with Curve Fitting
The question is a bit ambiguous. I do not see where curve fitting (actually parameter estimation) enters into it, because I do ...

5 days ago | 0

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Como resolver esta ecuacion
Is there a problem? This works — % Parámetros del sistema m = 45; % masa c = 64; % coeficiente de amortiguamiento k =...

5 days ago | 0

save a figure in a predefined folder as variable using print
Using the fullfile function may help. You have to supply the necessary information, however fullfile will build the path.

5 days ago | 0

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How to plot specified data points on a polar plot with curved lines, instead of straight lines
I am not certain what result you want. The plot image you posted looks like a sort of spline fit, however when I tried a spline...

6 days ago | 0

Sorting pairs into seperate matrices based on whether they are ascending or descending
The loop is not necessary anyway. Just use ‘logical indexing’ — pairs = [2 8 7 5 6 8 4 7 ...

6 days ago | 0

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I have line and want to colour the area behind the line (beyond the x axis) how can I do this
I am not completely certain what ‘behind’ the line means, however from your comments with respect to the x-axis, I guess that yo...

6 days ago | 0

Fit experimental data to analytical expression
Equation (3) is a bit mystifying to me. imshow(imread('analytical_expr.png')) imshow(imread('phase_vel.png')) I assume th...

7 days ago | 0

Convert a datetime to string
I am not certain what the problem is. To convert [2022 07 17] to your desired format using datetime, try this — DT = dateti...

7 days ago | 0

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unexpected discontinuity in graphic
My guess is that the filter is unstable. This occurs relatively frequently with transfer function realiations of filters. I ...

7 days ago | 0

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exponential regression functions with error in input values
There are other options, however everyone hass fminsearch, so using it — x = [4; 25; 100]; y = [100; 50; 0]; % objfcn = @...

7 days ago | 0

3D surface plot from only scalars
The only difference appears to be that whatever produced the plots in the posted image is using much higher precision and differ...

8 days ago | 0