Answered

lsim() vs step() : are different responses expected?

@John I was able to recreate your strange result on R2022a. After some investigation, I think I know what's happening. load ...

lsim() vs step() : are different responses expected?

@John I was able to recreate your strange result on R2022a. After some investigation, I think I know what's happening. load ...

2 months ago | 1

| accepted

Answered

Adding InternalDelay for State Space system

Hi John, I suspect the error message is telling you that you can only change the value of internal delays that already exist in...

Adding InternalDelay for State Space system

Hi John, I suspect the error message is telling you that you can only change the value of internal delays that already exist in...

2 months ago | 1

| accepted

Answered

How to plot the actual frequency range for the FFT plot?

clear all; close all; clc; %% Signal parameter c = 3e8; % speed of light fc= 10e9; % c...

How to plot the actual frequency range for the FFT plot?

clear all; close all; clc; %% Signal parameter c = 3e8; % speed of light fc= 10e9; % c...

2 months ago | 0

Answered

A weird feature in the obtained function from calculating the inverse Fourier transform using ifft

Hi Shaily_T, It looks like the purpose of the code is to linearly convolve an input signal with an impulse response via mulitip...

A weird feature in the obtained function from calculating the inverse Fourier transform using ifft

Hi Shaily_T, It looks like the purpose of the code is to linearly convolve an input signal with an impulse response via mulitip...

2 months ago | 1

Answered

Omega method to integrate sin function

Hi Tommaso, Starting with the acceleration as in the orginal code (I prefer to use row vectors) % use row vectors fs = 20; % ...

Omega method to integrate sin function

Hi Tommaso, Starting with the acceleration as in the orginal code (I prefer to use row vectors) % use row vectors fs = 20; % ...

2 months ago | 2

| accepted

Answered

How to find the correct magnitude/frequency value for FFT when there has noise?

Hi Hantao, Load the data x = readtable('Data.xlsx'); Time = x.Time; Current = x.Current; Plot it figure plot(Time,Current...

How to find the correct magnitude/frequency value for FFT when there has noise?

Hi Hantao, Load the data x = readtable('Data.xlsx'); Time = x.Time; Current = x.Current; Plot it figure plot(Time,Current...

2 months ago | 0

| accepted

Answered

Why is FFT result divided by NFFT instead of the root of NFFT?

Hi Miktat, The energy spectrum and the amplitude spectrum are two different things. Using the conventions of fft, the output yf...

Why is FFT result divided by NFFT instead of the root of NFFT?

Hi Miktat, The energy spectrum and the amplitude spectrum are two different things. Using the conventions of fft, the output yf...

2 months ago | 0

| accepted

Answered

Why does cconv perform worse than conv?

I ran this code where cconv outperforms conv for large n n = round(linspace(1e3,1e5,50)); n2 = 2.^(5:nextpow2(n(end))); n = s...

Why does cconv perform worse than conv?

I ran this code where cconv outperforms conv for large n n = round(linspace(1e3,1e5,50)); n2 = 2.^(5:nextpow2(n(end))); n = s...

2 months ago | 1

Answered

lsim() vs step() : are different responses expected?

The code and the system in the .mat file does not recreate the step plot. There is also an undefined variable. load sys.mat % ...

lsim() vs step() : are different responses expected?

The code and the system in the .mat file does not recreate the step plot. There is also an undefined variable. load sys.mat % ...

2 months ago | 0

Answered

What is being "averaged" in the matlab bandpower() function?

Hi Joey, I will confess to only having basic knowledge of this subject and suggest a thorough review of a good textbook. I'll t...

What is being "averaged" in the matlab bandpower() function?

Hi Joey, I will confess to only having basic knowledge of this subject and suggest a thorough review of a good textbook. I'll t...

2 months ago | 0

Answered

change class syms to double

Something like this ... e = exp(sym(1)) class(e) format long e = double(e) class(e)

change class syms to double

Something like this ... e = exp(sym(1)) class(e) format long e = double(e) class(e)

2 months ago | 0

Answered

ifft returns NaN when plotting the impulse response function

Hi 粤轩 杨, It looks like h_FFT also has a few values that are inf, in addition to the NaNs load("AIF_1.mat"); load("inj_1.mat")...

ifft returns NaN when plotting the impulse response function

Hi 粤轩 杨, It looks like h_FFT also has a few values that are inf, in addition to the NaNs load("AIF_1.mat"); load("inj_1.mat")...

2 months ago | 0

| accepted

Answered

Extract first and last row of each subarray in a cell array

I think this works even if the first and last row of a cell are identical. load(websave('cellArray.mat','https://www.mathworks....

Extract first and last row of each subarray in a cell array

I think this works even if the first and last row of a cell are identical. load(websave('cellArray.mat','https://www.mathworks....

2 months ago | 1

| accepted

Answered

Issues with subs function

I'm sure if you go through it step-by-step, or w/o assigning numbers until the end, you'll see that value of b1 is magical and a...

Issues with subs function

I'm sure if you go through it step-by-step, or w/o assigning numbers until the end, you'll see that value of b1 is magical and a...

2 months ago | 0

| accepted

Answered

plotting a surface between two curve

Hi M, Here's some code to get started. % small curve file_address = 'https://www.mathworks.com/matlabcentral/answers/uploaded...

plotting a surface between two curve

Hi M, Here's some code to get started. % small curve file_address = 'https://www.mathworks.com/matlabcentral/answers/uploaded...

2 months ago | 0

| accepted

Answered

convolution without conv function

Questions like this are fairly common on this forum. A closed form expression can be obtained using syms heaviside rectangula...

convolution without conv function

Questions like this are fairly common on this forum. A closed form expression can be obtained using syms heaviside rectangula...

2 months ago | 0

Answered

fplot and laplace transform

Based on the comment thread in the question, I think the best you can do symbolically would be some something like this: A = [-...

fplot and laplace transform

Based on the comment thread in the question, I think the best you can do symbolically would be some something like this: A = [-...

2 months ago | 1

Answered

Complex equation in MATLAB (control engineering)

Hi Michael, vpasolve found a solution, even if it's not the one you want. syms s syms w T real F_O = (exp(-s*T))/(s*(1+s)); ...

Complex equation in MATLAB (control engineering)

Hi Michael, vpasolve found a solution, even if it's not the one you want. syms s syms w T real F_O = (exp(-s*T))/(s*(1+s)); ...

2 months ago | 0

Answered

how to model this algorithm in simulink?

In the integrator block, set the "Initial Condition Source" to external. Then, connect that source to whatever logic you need t...

how to model this algorithm in simulink?

In the integrator block, set the "Initial Condition Source" to external. Then, connect that source to whatever logic you need t...

2 months ago | 0

Answered

Discretize State Space feedback controller using c2d()

Hi John, lqrd returns the gains for a discrete time controller. The Control System Toolbox cannot model hybrid systems, as far ...

Discretize State Space feedback controller using c2d()

Hi John, lqrd returns the gains for a discrete time controller. The Control System Toolbox cannot model hybrid systems, as far ...

2 months ago | 1

| accepted

Answered

Matlab function block and integration

If computing the instantaneous power as a function of time, why not feed that into an integerator to find the energy as a functi...

Matlab function block and integration

If computing the instantaneous power as a function of time, why not feed that into an integerator to find the energy as a functi...

2 months ago | 1

Answered

How to create a sine function from simulink blocks?

Why not just use a Sine Wave block? Would be a lot easier, and you can specify the sample time. The plot you're getting is most...

How to create a sine function from simulink blocks?

Why not just use a Sine Wave block? Would be a lot easier, and you can specify the sample time. The plot you're getting is most...

2 months ago | 0

| accepted

Answered

Linearize and Transfer Function

Does linearize do what you need? It can be used to linearize a model or a specific block in a model. Not sure how well it works...

Linearize and Transfer Function

Does linearize do what you need? It can be used to linearize a model or a specific block in a model. Not sure how well it works...

2 months ago | 1

Answered

remove annotations from diskmarginplot

Hi Muhammad, Something like this might work, either inside or after the loop. Some experimentation may be needed. Disk margin ...

remove annotations from diskmarginplot

Hi Muhammad, Something like this might work, either inside or after the loop. Some experimentation may be needed. Disk margin ...

2 months ago | 0

| accepted

Answered

How do I change variables so that I can differentiate with respect to a derivative?

Hi Curran, The doc page functionalDerivative has related example and shows the problem can be solved like this: % Symbols sy...

How do I change variables so that I can differentiate with respect to a derivative?

Hi Curran, The doc page functionalDerivative has related example and shows the problem can be solved like this: % Symbols sy...

2 months ago | 2

| accepted

Answered

Normalizing an FFT Vector

Hi bil, Define psi syms x real L = 100; psi(x) = sqrt(sym(2)/L)*sin(sym(pi)*x/L)*rectangularPulse(0,L,x); %particle in a box...

Normalizing an FFT Vector

Hi bil, Define psi syms x real L = 100; psi(x) = sqrt(sym(2)/L)*sin(sym(pi)*x/L)*rectangularPulse(0,L,x); %particle in a box...

2 months ago | 1

| accepted

Answered

Close loop bode plot

If you have a model of the plant and a model of the controller, it's likely that all that's needed is the feedback command to co...

Close loop bode plot

If you have a model of the plant and a model of the controller, it's likely that all that's needed is the feedback command to co...

2 months ago | 0

Answered

How does bandpower() round the input frequencies in variable 'freqrange'?

Hi Joey, bandpower is an .m file, at least in 2022a, so you can inspect the code. My reading is that it will compute the power...

How does bandpower() round the input frequencies in variable 'freqrange'?

Hi Joey, bandpower is an .m file, at least in 2022a, so you can inspect the code. My reading is that it will compute the power...

2 months ago | 0

| accepted

Answered

Symbolic acos( cos(theta) ) does not return theta.

simplify does provide an option that returns theta: syms theta real assume( theta >-1 & theta < 1) a = simplify( acos(cos(the...

Symbolic acos( cos(theta) ) does not return theta.

simplify does provide an option that returns theta: syms theta real assume( theta >-1 & theta < 1) a = simplify( acos(cos(the...

2 months ago | 0

Answered

I have a transfer function as shown, how do i introduce this block in simulink

Use a Tranport Delay block with Time Delay parameter of 0.2 in series with a Transfer Fcn with Numerator 1 and Denominator [0.1 ...

I have a transfer function as shown, how do i introduce this block in simulink

Use a Tranport Delay block with Time Delay parameter of 0.2 in series with a Transfer Fcn with Numerator 1 and Denominator [0.1 ...

2 months ago | 0