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How to use the index ? how to drop elements from a matrix ?
One of many ways: b= [ 0.0913 NaN NaN NaN 0.0913 NaN NaN NaN 0.0913 ...

12 years ago | 0

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how to filter a signal using firlpnorm???
Have you read the documentation for firlpnorm()? firlpnorm() seems like a sophisticated filter design for just a sine wave in ad...

12 years ago | 0

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How to randomly select entire row from matrix?
A = randn(198220,15); idx = sort(randperm(size(A,1),100)); B = A(idx,:);

12 years ago | 2

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Image processing from MATLAB to C
If you are going to start writing the code from scratch. I would consider openCV in the area of computer vision: <http://open...

12 years ago | 0

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3D to 2D matrix and then drop the NANS?
You can just reshape the transposes of each "page" c1 = reshape(b(:,:,1)',12,1); c2 = reshape(b(:,:,2)',12,1); C = [c1; ...

12 years ago | 0

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how to match both the side?
If it's a simple matter of assigning matrices, then your syntax works. outimg = zeros(256,256,3); out1img = ones(256,256);...

12 years ago | 0

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3D to 2D matrix and then drop the NANS?
A = reshape(b,24,1); A = A(~isnan(A));

12 years ago | 0

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Spectrogram windowing- why do the 2 methods generate different graphs?
That is a different question. The answer to that question is that calling spectrogram() with no output arguments is the same as ...

12 years ago | 0

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Spectrogram windowing- why do the 2 methods generate different graphs?
Here I use your signal and they are identical: FS = 100; w1=2; w2=5; w3=40; t=0:1/FS:10; dt = 1/FS; x = zero...

12 years ago | 0

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power spectral density PSD?
Hi Mary, If you have the Signal Processing Toolbox, the easiest thing is to use periodogram() I'll create some simulated sign...

12 years ago | 1

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Spectrogram windowing- why do the 2 methods generate different graphs?
Are you sure you are using MathWorks' version of spectrogram() and/or hamming()? Because I see no difference at all (and there s...

12 years ago | 0

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How long does a PCA anaysis take?
That depends on the size of the matrix. Have you tried it?

12 years ago | 0

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Why do I get the error message Error using calculate (line 2) Not enough input arguments.
You can't write a function definition that expects inputs a,b, and c and then only try to provide them with an input statement i...

12 years ago | 0

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how to generate and plot uniform distributions?
If you have the Statistics Toolbox -- unifpdf() For example, U(2,5) X = 2:0.01:5; A = 2; B = 5; ...

12 years ago | 0

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arima : why MA polynomial needs be invertible ?
MA models are required to be invertible because of non-uniqueness. For example, consider an MA(1) model: X_t = W_t+\theta W_{...

12 years ago | 0

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How to do complex bandpass filter in matlab?
You have to use cfirpm() not firpm() and then specify your constraints. For example: b = cfirpm(30,[-1 -.5 -.4 .7 .8 ...

12 years ago | 0

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Generating a single pulse in time?
See my earlier answer for how to do it. Using your if statement approach, when t is a vector how do you expect the if stateme...

12 years ago | 0

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Frequency content of a tachometer signal
Just looking at your signal, why would you expect anything more from the Fourier transform than energy at the fundamental freque...

12 years ago | 0

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spectral analysis for discontinuous time series data
You have a couple options: 1.) You can interpolate the missing data and obtain interpolated values for the missing data. 2...

12 years ago | 1

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How do you replace the entry of a matrix with a string?
You can't technically replace an entry of a matrix with an entire string. You would require a cell array for that. You can conve...

12 years ago | 1

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Generating a single pulse in time?
You did not tell us the sampling frequency so I'll just assume it is 1 Hz in my example. t = 0:1:1000; s = 0.01*o...

12 years ago | 0

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Matlab problem, not sure how to solve a certain simultaneous equation?
For a unit vector, cos(\theta) is just the x-coordinate and sin(\theta) is the y coordinate, so look at the help for atan2(). ...

12 years ago | 0

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Extract one element from row vectors?
In addition to Azzi's suggestion you can use A(A~=max(A)) but keep in mind that both will remove multiple values if the m...

12 years ago | 1

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Why is DFT phase different from FFT phase?
The DFT is a linear operator from \mathbb{C}^N to \mathbb{C}^N. Your vector sin(t) for the argument values you have defined i...

12 years ago | 0

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NANMEANs for each (n,m) position over several matrices with the same size
Not sure if this is what you're asking but: A=[1 2 NaN;4 5 6;7 NaN 9]; B=[NaN 2 3;NaN NaN 6;7 8 9]; C=[NaN NaN NaN;...

12 years ago | 0

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hanning ,hamming window in matlab?
If you have row vectors you have to make the necessary adjustment. Just convert them to column vectors. s1 = s1';

12 years ago | 1

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How can I use " imfindcircles" ?
Hi Christine, you may want to increase the sensitivity a bit. Here, use the file I attach and run the following code. im = ...

12 years ago | 0

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Find the last position of maximum value in a Matrix
You can use find() with the 'last' argument: x = randi([1 10],100,1); maxval = max(x); I = find(x==maxval,...

12 years ago | 0

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change the step in x label
Use 'xtick' I'll do an example with Gaussian distributed data but I doubt you really want to space the ticks for every integer. ...

12 years ago | 0

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hanning ,hamming window in matlab?
That depends on how they are in your workspace. If you have 20 separate vectors, then just do this. I'll assume they are colu...

12 years ago | 1