# 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 do get 'plumblines' for scatterplot points?

Use the stem3 function. If you want to colour the points, use something like this — figure stem3(X, Y, Z) hold on scat...

5 hours ago | 0

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what's the index exceed error?

The indexing problem is that ‘sig’ is preallocated as a vector: sig = zeros(1,405); % Preallocate the array Preallocating it ...

7 hours ago | 0

How to put time column at X axis from timetable against column 2,3,4 Y axis.

Perhaps something like this — TT = readtable(path_to_file); TT.Time = datetime(TT.Time, 'InputFormat','yyyy-MM-dd''T''HH:mm:s...

14 hours ago | 0

Finding a definite integral

Use the 'ArrayValued' name-value pair with integral — u = [0.1600 0.1600 0.1599 0.1599 0.1597 0.1596 0.1594 ...

1 day ago | 0

Removing Error Data from Table

This is definitely an interesting problem, and one I have thought about at other times. I am not certain that I have complete...

2 days ago | 0

Making an irregular cylinder using surface plotting

Here is one approach — S = rand(60,12); S = S.*((0:59).*exp(-0.1*(0:59))).'; figure surf(S) colormap(turbo) axis('equal...

2 days ago | 0

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Voltage find maximum of data

Try this — Table_1 = readtable('noise.txt'); Table_1.Properties.VariableNames = {'Time','Voltage'}; %Filter Filtered_Vol...

2 days ago | 0

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Smooth 2D colormap based on non-evenly distributed data

I am not certain that I understand what result you want. Try this — data = readmatrix('Data.txt'); figure scatter3(data...

3 days ago | 0

Discrete filter bode shows wrong results

The fault, if there is one, is in not understanding the Control System Toolbox conventions. Addition creates a system with the ...

3 days ago | 0

two versions of filter response

The only ones that I am aware of are the time domain response (showing both the unfiltered and filtered versions of the input si...

3 days ago | 0

griddedInterpolant error "Interpolation requires at least two sample points for each grid dimension."

The interpn function could be an option. You will need to experiment with the ndgrid function to determine how best to reshape ...

3 days ago | 0

power of 10 problem

‘... values of for example pressure were imported as text and not as number’ Use the str2double function to convert them to n...

3 days ago | 0

How do I open .bin file and transform data to .txt file

A ‘4-byte float’ is probably 'float32' (possibly 'real*4'), so one of those should work for the ‘precision’ argument in fread. ...

4 days ago | 0

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12 Lead ECG Problem

See Detecting QRS complex in ECG signal and how can I get cardioid graph from ecg QRS complex? for representative examples.

5 days ago | 0

Unrecognized function or variable 'knnimpute'

If you installed the Toolboxes using the installer, MATLAB should be able to access them. Your posted code works here — dat...

5 days ago | 0

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How do I find the minimum between a matrix and a varying matrix function? I get "Error in fmincon (line 563) initVals.f = feval(funfcn{3},X,varargin{:});"

There is one typo (. where _ should be) in: eps_dried = eps_dried.I3.epsilon; so change that to: eps_dried = eps_dried.I3_e...

6 days ago | 1

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How to get data points from graph

Getting information from .fig files has changed over the years. This approach works with the most recent releases. Use the f...

6 days ago | 0

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unsupervised thresholding of signal amplitudes: MLE?

I encourage you to investigate the ‘prominence’ values of the peaks. This is not a straightforward concept to define (see the f...

6 days ago | 0

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How to set up a plot with labels but no Y-axis tick marks

Perhaps this — figure boxchart(rand(10)) yt = yticks; yline(yticks, '-k', 'Color',[1 1 1]*0.25) Ax = gca; Ax.YAxis.Visibl...

6 days ago | 0

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How can I obtain the difference between two data stored in workspace?

If the two variables have the same number of elements, just subtract one from the other. For example: speed_error = refere...

7 days ago | 0

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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}; ...

7 days ago | 0

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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...

8 days 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...

8 days ago | 0

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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...

8 days ago | 0

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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...

9 days 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 ...

9 days ago | 1

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...

9 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}; ...

9 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...

11 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 ...

12 days ago | 0

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