# Star Strider

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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**Content Feed**

How can I plot this X and Y data?

Perhaps something like this — LD = load(websave('Tide_Data','https://www.mathworks.com/matlabcentral/answers/uploaded_files/12...

18 hours ago | 0

| accepted

how to separate a large text file into individual text files based on date, but also export headers?

Try something like this — files = {'https://www.mathworks.com/matlabcentral/answers/uploaded_files/1276100/Gwynedd_1991.txt';'...

20 hours ago | 0

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Is the window function automatically used when doing the fft function, or do I have to enter code to use the window function?

The fft defaults to a rectangular window that is the length of the signal. That is the only one that is ‘autoomatically’ used. ...

1 day ago | 0

Creating sounds with changing amplitude

Try this — Fs = 44100; Ft = 440; sec = 2; t = linspace(0, Fs*sec*60-1, Fs*sec*60).'/Fs; % ChkFrq = 1/t(2) s = sin(2*pi*Ft...

1 day ago | 0

How to interpret results of FFT/DFT?

The time vector needs to be scaled correctly if the frequency vector is to be correct. Try this — T1 = readtable('https://w...

1 day ago | 0

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Plot a graph from arrays

Try something like this — hv = [0,2,4,6,8]; Xm = [ {[54.8765]} {[15.8544]} {[55.3118]} {[19.0629]} {[55....

1 day ago | 0

Logical operator not evaluating correctly

Only two comparisons are actually required here — X = linspace(-7, 7, 15); Y = -(X < -5) + (X > 5); Check_Result = [X; Y] ...

1 day ago | 0

add the magnitude ratio and the phase angles data points on bode diagram

I am not certain what you want for the result. The fit is not the best, however the compare function will plot the data and t...

2 days ago | 0

How to plot a graph correctly?

I am not certain that I understand what you want to do. If you only want the contour at ‘F=0’, supply that as the fourth, ‘Le...

2 days ago | 0

How do I simplify a function?

You apparently defined some of those variables as arrays previously. To use the simplified function numerically, use the matl...

3 days ago | 0

How to covert rownames to the first variable in the table?

Try something like this — T1 = array2table(randi(9, 5, 5)); T1.Properties.RowNames = {'1','2','3','4','5'} ...

3 days ago | 0

How to calculate the derivative of vector

Fro symbolic variables, diff only works with funcitons. To calculate a numeric derivative, try something like this (assuming ...

4 days ago | 0

Ideal way to smoothe gyroscope data

The LPF approach is likely appropriate, and an IIR filter (elliptical is most efficient) is likely the best option. First, de...

4 days ago | 0

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How to remove the value using Histogram

I have only a vague idea of what you want to do, especially since the .mat file does not appear to contain the same data as depi...

4 days ago | 0

what is the correct way to write this expression in matlab?

If ‘R’, ‘L’, and ‘C’ are all arrays of the same size, use element-wise operations in every multiplication, division, and exponen...

4 days ago | 1

I'm really not good at this. "Array indices must be positive integers or logical values." What is wrong?

I suspect you want to define ‘u’ as a unit step function. This does that (and solves the ‘u’ error) however it gives a likely u...

5 days ago | 0

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How do I add rows to a table in a for loop?

The vertcat function needs to know what ‘NewRow’ is to be concatenated to. Try something like this — T1 = array2table(magic...

5 days ago | 0

time domain specifications calculations from graph

I am not certain what you want to do. Try something like this — sys = tf(4,[1 2 10]); si = stepinfo(sys); RT = si.RiseT...

5 days ago | 0

MATLAB error using fzero function

I have no idea what intersections you want to find, so this is a guess. It should at least get you started — % clear all; c...

5 days ago | 1

| accepted

How can you shift the position of x axis labels?

They’re probably text objects, however it’s not possible to access their properties. The only way to change them is to get them...

5 days ago | 0

| accepted

Unable to set the scatter3 marker color using clim

Perhaps something like this — scatter3(x, y, z, 50, z, 'filled', 'MarkerEdgeColor', 'none'); The fourth argument to scatter3 ...

6 days ago | 0

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How do I remove the tick marks on a bar plot at the top and the right?

Turn the Box property 'off', then use xline and yline to draw the lines — figure bar(rand(1,10)) Ax = gca; Ax.Box = 'off'...

6 days ago | 0

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PPG and Remote PPG peak detection

I went back to have another look at this. The two signals appear to have very little in common, even with respect to their Fo...

6 days ago | 0

latex in text doesn't work

Use two backslants (\\) in any sprintf call to ‘escape’ it — text(1, 1.5,sprintf('$\\tilde{y_x}$= %.3f',5), ... 'Interpre...

6 days ago | 0

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How to avoid determining P wave in PVC beat ?

There is no true P-deflection preceding a PVC. That is essentially the definition of a Premature Ventricular Contraction or P...

7 days ago | 0

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matlab plot legend bug

It is not possible to determine what the problem is without the data and a text (not image) version of the code. One option i...

7 days ago | 0

Error with plotting function

You will need to use element-wise operators with vector arguments. See Array vs. Matrix Operations for details. Use surf for...

7 days ago | 1

| accepted

Peak to peak amplitude

LD = load(websave('question_sample','https://www.mathworks.com/matlabcentral/answers/uploaded_files/1270450/question_sample.ma...

7 days ago | 0

| accepted

Having data on yearly basis but want to have it on monthly basis

This is not the correct approach. Interpolating yearly data to monthly data creates data where none previously existed. Once t...

7 days ago | 0

How to sample from a distribution?

‘How do you use randsample (or maybe something else?) to sample from a distribution?‘ The random function can be used with kno...

8 days ago | 0

| accepted