# 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)

**Statistics**

RANK**3**

of 295,068

REPUTATION**67,284**

CONTRIBUTIONS

**0** Questions

**20,426** Answers

ANSWER ACCEPTANCE **
0.00%
**

VOTES RECEIVED**9,465**

RANK**2,556** of 20,171

REPUTATION**660**

AVERAGE RATING**4.70**

CONTRIBUTIONS**5** Files

DOWNLOADS **17**

ALL TIME DOWNLOADS**6101**

CONTRIBUTIONS**0 Posts**

CONTRIBUTIONS**0** Public Channels

AVERAGE RATING

CONTRIBUTIONS**0** Highlights

AVERAGE NO. OF LIKES

**Feeds**

Assistance Needed with FIR Comb Peak and Notch Filter Design in MATLAB

The peak filter was a bit challenging, however I got it to work reasonably well. The comb filter may not exactly meet your de...

20 hours ago | 1

| accepted

curve fitting using lsqcurvefit on kinetic data for parameter estimation

The model itself is a bit misleading. A better option might be: That produces an equivalent fit with paramete...

23 hours ago | 0

| accepted

Detect main part of a signal

I usually use the envelope function, usually using the 'peak' option, and then test for the first instance of those (ususlly the...

2 days ago | 0

FFT result dependent on number of interpolation points

The interpft function is intended to interpolate the Fourier transform, and it does a reasonably good approximation. I checked ...

5 days ago | 0

Convert string into datetime

It would help to have the file. Try this — Date_Time_rural = ["2023-10-31 00:00:00"; "2023-11-01 00:00:00"; "2023-11-02 00...

5 days ago | 0

Fourier Series Representation of Periodic Functions

I would write the piecewise call differently — syms t omega a_k = piecewise(0 <= t < 0.4, 1, 0.4 <= t < 0.5, -1) figure ...

6 days ago | 0

I am taking two excel files with similar x value data and want to plot the y values of one of the plots with different colors based on if the second file reads 0 or 1.

This is something of a challenge. In order to be able to use both records, it is necessary to intterpolatee the shorter record ...

7 days ago | 0

Why does the phase response get cutoff beyond a frequency?

The most likely reason is that the filter numerator coefficients are close to the limit of floating-point approximation error. ...

7 days ago | 1

| accepted

finding relation between two variables, being discharge and water level in a river

Your question is a bit ambiguous. If you have data of some sort and you want to fit that model to it in order to deteermine ...

7 days ago | 0

| accepted

Slope of some groups of data separated by NaNs

I am not certain what you want for ‘values’. This prints the equation of the regression line for each line — load('data_min...

7 days ago | 0

| accepted

Site Response Analysis - FFT

Just looking at your code (without having the data), one problem could be that your amplification function is defined only over ...

8 days ago | 0

convert time domain data to frequency domain

There are 6839 missing (non-sequential) rows in this file, so to use fft you will first have to interpolate them so they are seq...

8 days ago | 0

| accepted

plomb ifft sequence??? please help me!!!!

The plomb function returns the power spectral density of the input time-domaiin signal. In order to do in inversee Fourier tran...

9 days ago | 0

How to extract areas of contourf-plots below a given level

It is a bit difficult to follow your code. In my additions, these lines: idx = find(contourData(1,:) == contourLevel); cle...

10 days ago | 0

Hi, I want to how can we convert the contour geometry to stl file?

Try something like this — % clc; clear; close all; % Generating simple SDF [x, y] = meshgrid(linspace(-2, 2, 100), linspac...

11 days ago | 1

| accepted

Skipping Optional Positional Arguments

I usually use varargin rather than arguments, however your calling syntax may not be appropriate To illustrate — out = foo(1,...

12 days ago | 0

Creating a sinewave with logarithmic frequency

Using the logspace function could work. Try this ’— % Generate log-frequency sweep then plot it and its spectrogram NPTS...

13 days ago | 0

| accepted

How to plot a 2D pcolor with contours only at specific levels?

Using the vector works here, and your code runs without error in R2024b — load('data.mat') whos('-file','data') pcolor(lon...

13 days ago | 0

| accepted

Default bode axis to Hz in R2024b

I did not see any changes to that in the Release Notes, however that does not mean that they were not changed. The only relevan...

13 days ago | 1

Downsampling array data from counts per minute to counts per hour

That depends on what you want to do. I would use a timetable and the retime function — Time = datetime(2004,10,23,17,00,00)...

14 days ago | 0

| accepted

Interpolate missing hourly and daily data

Usee the retime function with a timetable — filename = "Missing_data.xlsx"; T1 = readtable(filename); T1.Properties.Variable...

14 days ago | 0

How to fit an XRD pattern to ambient solid and liquid patterns to extract qualitatively solid and liquid fractions?

It depends what the pattern is, and whether it is 2D or 3D. MATLAB has several fitting (parameter estimation and optimisation...

15 days ago | 0

how do I fprintf a power?

Using ‘char(178)’ is an option — gof.rsquare = 0.975; fprintf("R"+char(0178)+"; %.4f%s%.4f\n", gof.rsquare) .

15 days ago | 0

| accepted

MATLAb Solve function not solving

Your code works in R2024b — clear all close all syms I1 I2 V0 s=2; eqns=[5*I1+4*I2+1/(s*0.1)*I1+2*s*I1==1, 4*I2-3*V0==...

16 days ago | 1

ode45 integration issues for some choices of physical parameters,

‘I'm not aware of any division by zero being performed;’ The denominator does not have to be equal to zero, it just has to be...

16 days ago | 0

| accepted

resample function possibly introducing phase shift

If the original data are not regularly sampled, that could account for the distortion. (An easy way tto check this is to calcul...

16 days ago | 0

How to choose 60 unique coordinates ('A') from 600 coordinates('B'), nearest to 60 other coordinates('C')

Using pdist2 is an option — C = rand(60,2); B = rand(600,2); [A,I] = pdist2(B,C,'euclidean','smallest',1) figure scat...

16 days ago | 0

How to pass multiple arguments to a function handle?

An example of what you want to do could help. Perhaps something like this — for k = 1:10 k arg = randn(1,k) ...

16 days ago | 0

Two lines of plot title with number and date time

You cann do what yu want with string, " " arrays (or variables). Try this — load('title_data.mat') whos('-file','title_dat...

17 days ago | 1

How to use retime to get the plot of mean and stdev in continous time series

The correct way to express the deviation of cata around the mean is to use the standard error of the mean, given by: where ...

18 days ago | 0

| accepted