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

Solution of natural frequency equation with fzero function

The fzero function is likelly not appropriate here. I would instead use fsolve, and convert the obsolete inline call to an anon...

Solution of natural frequency equation with fzero function

The fzero function is likelly not appropriate here. I would instead use fsolve, and convert the obsolete inline call to an anon...

27 minutos ago | 0

Answered

a problem with power spectrum calculation (FFT)

The mean of ‘data’ is -16657.4418730469. This is the D-C component, so it appears at 0 Hz, and completely prevents the details ...

a problem with power spectrum calculation (FFT)

The mean of ‘data’ is -16657.4418730469. This is the D-C component, so it appears at 0 Hz, and completely prevents the details ...

alrededor de 1 hora ago | 0

| accepted

Answered

Comapring Values in one Matrix to another

Another approach: A = [373 383 393 403 413 420 451 485 499]; B = [373 453 457 461 464]; C = ones(numel(B),1)*A; ...

Comapring Values in one Matrix to another

Another approach: A = [373 383 393 403 413 420 451 485 499]; B = [373 453 457 461 464]; C = ones(numel(B),1)*A; ...

alrededor de 3 horas ago | 0

Answered

How to mark the maximum points in mesh

Add this loop just before the mesh call: for k = 1:size(Response_amp,1) [Ramax(k),Idx(k)] = max(Response_amp(k,:)); ...

How to mark the maximum points in mesh

Add this loop just before the mesh call: for k = 1:size(Response_amp,1) [Ramax(k),Idx(k)] = max(Response_amp(k,:)); ...

alrededor de 5 horas ago | 0

Answered

plot curve in matlab

syms qa h = (611375/279 - ((192500000*cos(qa))/93 + ((60000*cos(qa))/31 - 611375/93)^2/9 - 14656250/31)/(2*((153125000000*cos(...

plot curve in matlab

syms qa h = (611375/279 - ((192500000*cos(qa))/93 + ((60000*cos(qa))/31 - 611375/93)^2/9 - 14656250/31)/(2*((153125000000*cos(...

alrededor de 5 horas ago | 0

Answered

I need to find the angle from horizontal that tangents to a curve make for multiple points

I am not certain what you want to do, or the result you want. The easiest way to calculate numerical derivatives is to use th...

I need to find the angle from horizontal that tangents to a curve make for multiple points

I am not certain what you want to do, or the result you want. The easiest way to calculate numerical derivatives is to use th...

alrededor de 18 horas ago | 0

Answered

Interpolation to find harmonics from fft

Consider increasing the frequency resolution by using a longer fft. That may make it easier to detect the harmonics where you e...

Interpolation to find harmonics from fft

Consider increasing the frequency resolution by using a longer fft. That may make it easier to detect the harmonics where you e...

alrededor de 22 horas ago | 0

Answered

Reading Files and plotting in matlab

I am not certain what the responses to the input calls should be, so I did not run your code, only looked at it. It appears ...

Reading Files and plotting in matlab

I am not certain what the responses to the input calls should be, so I did not run your code, only looked at it. It appears ...

1 día ago | 0

| accepted

Answered

system of nonlinear equation

That is not going to woork with fsolve for a number of reasons. It is necessary to convert ‘f’ to a numeric (not symbolic) fu...

system of nonlinear equation

That is not going to woork with fsolve for a number of reasons. It is necessary to convert ‘f’ to a numeric (not symbolic) fu...

1 día ago | 0

Answered

Variables under the same name in different .mat files

Use load to load each of the files into a different structure. See Load List of Variables into Structure Array. You can then...

Variables under the same name in different .mat files

Use load to load each of the files into a different structure. See Load List of Variables into Structure Array. You can then...

1 día ago | 0

Answered

Looking for documentation explaining M.' and other symbols to select data from an array

‘M. means the same as M(:,:)‘ No, not ‘M.’. The extra dot will throw an error. I am not certain what you are asking. S...

Looking for documentation explaining M.' and other symbols to select data from an array

‘M. means the same as M(:,:)‘ No, not ‘M.’. The extra dot will throw an error. I am not certain what you are asking. S...

1 día ago | 0

Answered

Creating a vector of datetimes with increments of 15 minutes

Try this: Timestamp = (datetime('2020-06-30 23:45:00') : -minutes(15) : datetime('2015-01-01 00:00:00')).'; Timestamp.Format ...

Creating a vector of datetimes with increments of 15 minutes

Try this: Timestamp = (datetime('2020-06-30 23:45:00') : -minutes(15) : datetime('2015-01-01 00:00:00')).'; Timestamp.Format ...

1 día ago | 0

| accepted

Answered

simple question of creating a time vector

Without the exact details of your file (that I suspect is not exactly 60 seconds long), something like this will work: t = lin...

simple question of creating a time vector

Without the exact details of your file (that I suspect is not exactly 60 seconds long), something like this will work: t = lin...

1 día ago | 0

Answered

different sound file times

If you want all of the sound files to have the same sampling frequency, use the Signal Processing Toolbox resample function. On...

different sound file times

If you want all of the sound files to have the same sampling frequency, use the Signal Processing Toolbox resample function. On...

2 días ago | 0

Answered

There is something wrong in R.

The problem is in the way you call the exp function. This works: R = ((2.*h).*(f.^3))./((c.^2).*(exp(h.*f/(k.*T))-1)); .

There is something wrong in R.

The problem is in the way you call the exp function. This works: R = ((2.*h).*(f.^3))./((c.^2).*(exp(h.*f/(k.*T))-1)); .

2 días ago | 1

| accepted

Answered

Plot AREA limit in matlab

If you want the area between ‘abb_per’ and 100 filled, use the patch function. Try this: figure patch([n fliplr(n)],[abb_p...

Plot AREA limit in matlab

If you want the area between ‘abb_per’ and 100 filled, use the patch function. Try this: figure patch([n fliplr(n)],[abb_p...

2 días ago | 0

| accepted

Answered

lowpass() not working

A low passband with a very high sampling frequency is asking a lot of any filter. I am somewhat surprised that lowpass used a F...

lowpass() not working

A low passband with a very high sampling frequency is asking a lot of any filter. I am somewhat surprised that lowpass used a F...

2 días ago | 0

Answered

How to plot 3D surface with vector-input function?

The function you coded: FUN = @(x) = x(1).^2+x(2).^2; will only take the first 2 elements of ‘x’ (whatever it is), and will r...

How to plot 3D surface with vector-input function?

The function you coded: FUN = @(x) = x(1).^2+x(2).^2; will only take the first 2 elements of ‘x’ (whatever it is), and will r...

3 días ago | 0

| accepted

Answered

piecewise for use in anonymous functions

One option: Rt0 = @(theta,theta1,theta2,B,H,L1) ((0<=theta) & (theta<theta1)).*(B./2+L1)./cos(theta) + ((theta1<=theta) & (the...

piecewise for use in anonymous functions

One option: Rt0 = @(theta,theta1,theta2,B,H,L1) ((0<=theta) & (theta<theta1)).*(B./2+L1)./cos(theta) + ((theta1<=theta) & (the...

3 días ago | 1

Answered

extract mth and m+1st largest element from a vector

‘Is using sort is the best way?’ Yes.

extract mth and m+1st largest element from a vector

‘Is using sort is the best way?’ Yes.

3 días ago | 0

Answered

How to write a multi line string?

Since ‘tran_models’ is an array, just use a loop: for k = 1:size(tran_models,1) fprintf(File,'%s\n', tran_models(k,:)); ...

How to write a multi line string?

Since ‘tran_models’ is an array, just use a loop: for k = 1:size(tran_models,1) fprintf(File,'%s\n', tran_models(k,:)); ...

3 días ago | 0

| accepted

Answered

How can I plot and reach to this figure ?

birthday = datenum(year, month, day); t = 0:ceil(datenum(now)-birthday); Physical = sin(2*pi*t/23); The rest would be calcula...

How can I plot and reach to this figure ?

birthday = datenum(year, month, day); t = 0:ceil(datenum(now)-birthday); Physical = sin(2*pi*t/23); The rest would be calcula...

3 días ago | 0

Answered

Solving the Kinetic equations by Matlab coding

Try this: % % % k(1) = R_Inf, k(2) = k R1fcn = @(k,t) k(1).*(1-exp(-k(2).*t)); R2fcn = @(k,t) k(1).*(1 - (1-exp(-k(2).*t))...

Solving the Kinetic equations by Matlab coding

Try this: % % % k(1) = R_Inf, k(2) = k R1fcn = @(k,t) k(1).*(1-exp(-k(2).*t)); R2fcn = @(k,t) k(1).*(1 - (1-exp(-k(2).*t))...

3 días ago | 0

Answered

Changing scientific notation to long format

Select an appropriate option (such as long g) with the format function.

Changing scientific notation to long format

Select an appropriate option (such as long g) with the format function.

3 días ago | 0

| accepted

Answered

Plot fft and peaks on same plot

You did not provide ‘x’ or any of the parameters (such as ‘Fs’) so it is not possible to run your code, and you could easily hav...

Plot fft and peaks on same plot

You did not provide ‘x’ or any of the parameters (such as ‘Fs’) so it is not possible to run your code, and you could easily hav...

3 días ago | 0

| accepted

Answered

How to repeat the same graph?

Try this: t = 0:40; y = exp(-0.385*t) + 10; y6 = repmat(y, 1, 6); t6 = 0:numel(y6)-1; figure plot(t6, y6) grid produc...

How to repeat the same graph?

Try this: t = 0:40; y = exp(-0.385*t) + 10; y6 = repmat(y, 1, 6); t6 = 0:numel(y6)-1; figure plot(t6, y6) grid produc...

3 días ago | 0

| accepted

Answered

How to do segmentation on ECG signal for feature extraction

Use the Signal Processing Toolbox buffer function. Calculating ‘n’ is straightforward: n = 10 * 250 producing: n = ...

How to do segmentation on ECG signal for feature extraction

Use the Signal Processing Toolbox buffer function. Calculating ‘n’ is straightforward: n = 10 * 250 producing: n = ...

3 días ago | 1

Answered

Toolbox of Genetic Programming

Download and install the Global Optimization Toolbox. Simple genetic algorithm code is relatively easy to write. It does not...

Toolbox of Genetic Programming

Download and install the Global Optimization Toolbox. Simple genetic algorithm code is relatively easy to write. It does not...

3 días ago | 0

Answered

how to plot 2 curve with together

First, use element-wise multiplication and division: m=0:0.01:50; f= ((7*m - 7*(m.^2 - (226*m)/7 + 15009/49).^(1/2) + 127)...

how to plot 2 curve with together

First, use element-wise multiplication and division: m=0:0.01:50; f= ((7*m - 7*(m.^2 - (226*m)/7 + 15009/49).^(1/2) + 127)...

3 días ago | 1

Answered

If statement for input value

I would just use a loop: n = input('how many ingredients do you have'); %%FOOD INPUT for k = 1:n a(k) = input(sprintf('...

If statement for input value

I would just use a loop: n = input('how many ingredients do you have'); %%FOOD INPUT for k = 1:n a(k) = input(sprintf('...

3 días ago | 1

| accepted