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.

Answered

Position and extraction of row

It would definitely help to see what ‘mergetable1’ is, and how you are getting ‘AccelSN’. If ‘AccelSN’ is read as a string (f...

Position and extraction of row

It would definitely help to see what ‘mergetable1’ is, and how you are getting ‘AccelSN’. If ‘AccelSN’ is read as a string (f...

alrededor de 10 horas ago | 0

| accepted

Answered

signal fourier transform include unit step function

Try this version of your code: syms t x(t) % t = linspace(-20, 20, 5000); % u = @(t) (t >= 0); x(t) = exp(-t) * heaviside...

signal fourier transform include unit step function

Try this version of your code: syms t x(t) % t = linspace(-20, 20, 5000); % u = @(t) (t >= 0); x(t) = exp(-t) * heaviside...

alrededor de 12 horas ago | 0

| accepted

Answered

Matlab dsolve function issue with format.

My (R2020a) version requires slightly different symbolic convetions. Try this: syms x(t) Dx = diff(x); D2x = diff(Dx); e...

Matlab dsolve function issue with format.

My (R2020a) version requires slightly different symbolic convetions. Try this: syms x(t) Dx = diff(x); D2x = diff(Dx); e...

alrededor de 13 horas ago | 0

| accepted

Answered

Extraplotation of impedance data

First, I doubt that extrapolating from 250 kHz to 10 MHz is appropriate in any event. However it could be, if you identified ...

Extraplotation of impedance data

First, I doubt that extrapolating from 250 kHz to 10 MHz is appropriate in any event. However it could be, if you identified ...

alrededor de 13 horas ago | 0

Answered

Why I can't use the function of decimate

I get the same result as in the documentation (in R2020a). First, what version of MATLAB are you using? The current online d...

Why I can't use the function of decimate

I get the same result as in the documentation (in R2020a). First, what version of MATLAB are you using? The current online d...

alrededor de 14 horas ago | 0

Answered

determine the R waves to evaluate the ECG signal and determine the heart rate.

Use findpeaks or islocalmax to locate the R-wave peaks.

determine the R waves to evaluate the ECG signal and determine the heart rate.

Use findpeaks or islocalmax to locate the R-wave peaks.

alrededor de 20 horas ago | 0

Answered

Rolve function around axis to create 3D surface.

See: Plotting an exponential exp(-x), in 3D? for an example.

Rolve function around axis to create 3D surface.

See: Plotting an exponential exp(-x), in 3D? for an example.

1 día ago | 1

| accepted

Answered

Error using ss. How do i fix this?

Transpose ‘BS’ to a column vector (everywhere you use it, since you re-define it): BS=[0 0 0 0 0 0 k4/m4 0].'; Do the same f...

Error using ss. How do i fix this?

Transpose ‘BS’ to a column vector (everywhere you use it, since you re-define it): BS=[0 0 0 0 0 0 k4/m4 0].'; Do the same f...

1 día ago | 1

Answered

display result (numbers)

I suspect the problem is your format setting. Set it to: format long ps1=((max(max(X1))-mean(mean(X2)))/ (std2(X2))) and s...

display result (numbers)

I suspect the problem is your format setting. Set it to: format long ps1=((max(max(X1))-mean(mean(X2)))/ (std2(X2))) and s...

1 día ago | 0

Answered

Initial Conditions for first derivative defined as a transfer function

Apparently, step does not allow initial conditions to be stated, however initial does, and produces an impulse response plot giv...

Initial Conditions for first derivative defined as a transfer function

Apparently, step does not allow initial conditions to be stated, however initial does, and produces an impulse response plot giv...

1 día ago | 0

Answered

turning functions into floating-point numbers

Your question lacks detail. If you have an expression in one or more variables, you can express it as a function (most likely a...

turning functions into floating-point numbers

Your question lacks detail. If you have an expression in one or more variables, you can express it as a function (most likely a...

2 días ago | 0

Answered

need help on nomenclature, Simplify symbolic variables

If simplify is not simplifying to the extent that you want it to, use the Steps name-value pair to tell it to keep simplifying u...

need help on nomenclature, Simplify symbolic variables

If simplify is not simplifying to the extent that you want it to, use the Steps name-value pair to tell it to keep simplifying u...

2 días ago | 0

| accepted

Answered

create yyyymm variable from date

Try this: dt = '1/1/2020'; Out = datetime(dt, 'InputFormat','MM/dd/yyyy', 'Format','yyyyMM') producing: Out = dateti...

create yyyymm variable from date

Try this: dt = '1/1/2020'; Out = datetime(dt, 'InputFormat','MM/dd/yyyy', 'Format','yyyyMM') producing: Out = dateti...

2 días ago | 0

| accepted

Answered

Resampling Data using Interp1

You are doing signal processing. For that, use the resample function. It will do the interpolation, and will also use an anti-...

Resampling Data using Interp1

You are doing signal processing. For that, use the resample function. It will do the interpolation, and will also use an anti-...

2 días ago | 0

Answered

Can ode45 be used to solve mx'' + cx' + kx^1.1=0 x(0)=5;x'(0)=0? Getting complex numbers in answers.

You need to plot the real and complex parts separately. Assuming: [t,y] = ode45(yourOdefcn, tspan, ic); plot it as: fig...

Can ode45 be used to solve mx'' + cx' + kx^1.1=0 x(0)=5;x'(0)=0? Getting complex numbers in answers.

You need to plot the real and complex parts separately. Assuming: [t,y] = ode45(yourOdefcn, tspan, ic); plot it as: fig...

2 días ago | 0

Answered

How to show numeric solution instead of symbolic solution

The ‘q_dot’ variable cannot be expressed as a strictly numeric array because it contains symbolic variables. The best you can...

How to show numeric solution instead of symbolic solution

The ‘q_dot’ variable cannot be expressed as a strictly numeric array because it contains symbolic variables. The best you can...

2 días ago | 0

| accepted

Answered

Jacobian matrix of a numeric matri

See if the gradient function will do what you want. That is likely as close as you can get for a numeric matrix. If it is a ...

Jacobian matrix of a numeric matri

See if the gradient function will do what you want. That is likely as close as you can get for a numeric matrix. If it is a ...

3 días ago | 0

Answered

Second Order ODE with Power

The best way to integrate it numerically is something like this: syms x(t) A B C D vb b Y t v=diff(x,t,2)==(A/x)*(B+C*(diff(...

Second Order ODE with Power

The best way to integrate it numerically is something like this: syms x(t) A B C D vb b Y t v=diff(x,t,2)==(A/x)*(B+C*(diff(...

3 días ago | 0

| accepted

Answered

Running data through a filter multiple times

It is not easy to follow what you are doing here, especially with respect to your using the strings as part of the subscript (th...

Running data through a filter multiple times

It is not easy to follow what you are doing here, especially with respect to your using the strings as part of the subscript (th...

3 días ago | 1

| accepted

Answered

How to correctly apply bandpass filter to EEG data?

The bandpass function (and its friends) in my experience have all used filtfilt to do the actual filtering, so there should not ...

How to correctly apply bandpass filter to EEG data?

The bandpass function (and its friends) in my experience have all used filtfilt to do the actual filtering, so there should not ...

3 días ago | 0

Answered

findpeaks returns wrong width

If you have the Signal Processing Toolbox, use the pulsewidth function for this: D = readmatrix('test.csv'); A1 = D(:,2); t1...

findpeaks returns wrong width

If you have the Signal Processing Toolbox, use the pulsewidth function for this: D = readmatrix('test.csv'); A1 = D(:,2); t1...

4 días ago | 0

| accepted

Answered

genetic algorithm for curve fitting

I would do something like this (with ‘M’ and the constants already existing in your workspace): MFit = @(c0,M0,h,z,z0) (M0 + c...

genetic algorithm for curve fitting

I would do something like this (with ‘M’ and the constants already existing in your workspace): MFit = @(c0,M0,h,z,z0) (M0 + c...

4 días ago | 1

| accepted

Answered

remove first value that appears after sequence of NaNs

Try this: D = readmatrix('example_data.xlsx'); R01 = strfind(isnan(D(:,1)).', [1 0]); % Find Indices Of [0 1...

remove first value that appears after sequence of NaNs

Try this: D = readmatrix('example_data.xlsx'); R01 = strfind(isnan(D(:,1)).', [1 0]); % Find Indices Of [0 1...

4 días ago | 1

| accepted

Answered

I am trying to find the average of a 58 x 1000 matrix and the result should be a 58 X 48 matrix.

I am not certain that what you want to do is possible. I would normally suggest using reshape with it, then take the mean of ea...

I am trying to find the average of a 58 x 1000 matrix and the result should be a 58 X 48 matrix.

I am not certain that what you want to do is possible. I would normally suggest using reshape with it, then take the mean of ea...

4 días ago | 0

Answered

matrix dimension mismatch problem

The assignment to ‘Rb’ appears to be missing. Since you are using element-wise division wih it, it appears to be a vector, so I...

matrix dimension mismatch problem

The assignment to ‘Rb’ appears to be missing. Since you are using element-wise division wih it, it appears to be a vector, so I...

4 días ago | 0

Answered

confusion regarding interp1 command?

The two methods do not produce exactly the same results, however with respect to the amplitude of the values in the plot, they o...

confusion regarding interp1 command?

The two methods do not produce exactly the same results, however with respect to the amplitude of the values in the plot, they o...

4 días ago | 0

| accepted

Answered

Allow Maximum frequency in FFT to be lower than the sampling frequency

The maximum frequency for a sampled signal is the Nyquist frequency, half the sampling frequency. Here: Fs = 262144; Fn = ...

Allow Maximum frequency in FFT to be lower than the sampling frequency

The maximum frequency for a sampled signal is the Nyquist frequency, half the sampling frequency. Here: Fs = 262144; Fn = ...

5 días ago | 0

Answered

How to find the integral of some values?

use the trapz (or cumtrapz) function (depending on the result you want). It would be best to also have an independent variable ...

How to find the integral of some values?

use the trapz (or cumtrapz) function (depending on the result you want). It would be best to also have an independent variable ...

5 días ago | 0

| accepted

Answered

How can I bring patch in front of a surface plot?

The patch call does not define the ‘Z’ level, so by default it is zero. Change that to put it where you want it (this puts it a...

How can I bring patch in front of a surface plot?

The patch call does not define the ‘Z’ level, so by default it is zero. Change that to put it where you want it (this puts it a...

6 días ago | 0

| accepted

Answered

Enzymatic reaction modeling in MATLAB

You are not actually estimating parameters, however the example in: Parameter Estimation for a System of Differential Equations ...

Enzymatic reaction modeling in MATLAB

You are not actually estimating parameters, however the example in: Parameter Estimation for a System of Differential Equations ...

6 días ago | 0

| accepted