Answered
detect row and column
X = randn(10,5); min(X,[],1) min(X,[],2) max(X,[],1) max(X,[],2)

14 years ago | 0

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Answered
extract sub matrix of sub matrix directly
Yes, C = a(1:4,1:4,1);

14 years ago | 3

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Answered
define double(img(:,:,1))
That code is casting the first "page" of img (a 3D array) to type double. So perhaps img is uint8 to begin with (or something...

14 years ago | 0

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Passing a string to a function
namestruct = 'test'; test = struct('x',randn(100,1),'y',randn(100,1)); namez = fieldnames(eval(namestruct))

14 years ago | 0

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Answered
butterworth filter
Hi Sam, You must contact MathWorks for licensing a new toolbox in your installation. And please do follow Honglei's good advice ...

14 years ago | 0

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butterworth filter
Hi Sam, do you have the Signal Processing Toolbox installed? if you enter >>ver do you see an entry for Signal Proce...

14 years ago | 0

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creata random plot
Do you want the points to all have radius 10? or can they have random length up to 10? If it's the former: phaseang = ...

14 years ago | 0

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need syntax
One way x = ones(10,1); x = [x ; zeros(10,1)]; Another way: x = ones(10,1); y = zeros(10,1); x = vertcat(x,...

14 years ago | 0

Answered
Is it possible to add plots to an already existing graph?
If you use hold on, you should be able to do that. plot(randn(100,1)); hold on; plot(randn(100,1),'r'); plot(randn...

14 years ago | 0

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Answered
fir and iir filtering
You have to know your filter specifications. If you do, you can do both with fdesign.lowpass and fdesign.highpass fdesign.low...

14 years ago | 0

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Answered
difference between ASV file and m-file
This is just the autosave feature for .m files. Please see: <http://www.mathworks.com/company/newsletters/digest/nov03/auto_b...

14 years ago | 2

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Answered
Discrepancies between Power Spectra and Data
Hi Linford, A sampling frequency of 100 Hz (dt=0.01) is going to result in aliasing for the content from 50-70 Hz. As far as you...

14 years ago | 2

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Answered
units pmtm
The output from pmtm() the power spectral density will be in m^2/Hz (if you are using the sampling frequency). You want to make ...

14 years ago | 0

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Answered
How do I perform discrete wavelet frame fusion?
The Wavelet Toolbox has an image fusion demo. You can view that demo by entering >>edit imagefusiondemo.m

14 years ago | 0

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Answered
AR model spectral analysis of temperature signal
Hi Suji, The Signal Processing Toolbox enables you to obtain parametric (AR) spectral estimates using a few different algorithms...

14 years ago | 0

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Autocorrelations and Correlogram
Hi Linford, If you use xcorr() with the 'coeff' option you get the normalized autocorrelation sequence which does not exceed 1 i...

14 years ago | 0

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Answered
adding data to a text file
You can use: dlmwrite('FILENAME',M,'-append') For example: x = [2 7 3; 2 6 9]; dlmwrite('test.dat',x); y = [1...

14 years ago | 2

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Answered
1x100 vector of all -1
x = -1*ones(1,100); y = 2.00049*ones(1,100);

14 years ago | 0

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How to get specific data from Double?
Do you just mean? B = squeeze(A(25,25,:));

14 years ago | 0

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f(x)=3x^2+2x+9 to [3 2 9]
syms x; y = 3*x^2+2*x+9 coeffs(y) That gives you the coefficients ordered from lowest power of x to the highest. O...

14 years ago | 0

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Answered
Why with even numbers the sin looks completly different that with odd number
Nicolas, the problem is with your use of linspace(). The way you are using it you are generating a vector with 100 points equall...

14 years ago | 1

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Answered
FFT Analysis of two signals
Let's assume that x is one signal and y is the other signal. If you have the Signal Processing Toolbox, you can quickly compare ...

14 years ago | 0

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Answered
undecimated discrete wavelet transform
Midhun, you cannot use dwt() that is the decimated discrete wavelet transform. Please see the help for swt() or ndwt() as I s...

14 years ago | 0

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hrv spectral analysis
Hi Olga, I think your problem is that your frequency resolution is too poor. You are only obtaining PSD estimates at steps of...

14 years ago | 0

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Answered
how to take the average of a matrix of any size
mean() X = randn(100,100); mean(mean(X)) or mean(X(:))

14 years ago | 1

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yule walker psd
You can use the following syntax: pyulear(b1,20,[],Fs) where Fs is your sampling frequency.

14 years ago | 0

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Answered
Plotting 150 datapoints on a 360datapoint scale.
You can do the same thing as in Excel, you can upsample the vector by two and plot that. Or you can interpolate to get an est...

14 years ago | 0

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undecimated discrete wavelet transform
If you have the Wavelet Toolbox, there are undecimated wavelet transform routines in that toolbox: ndwt and swt

14 years ago | 0

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visualizing the fourier transform of pseudo random sequence with Matlab
By pseudo random sequence do you mean a white noise sequence created with something like randn()? If so, why would that have a s...

14 years ago | 0

Answered
Result Convolution/ multiplication in freq domain not the same
Without going into your code too much, since you are dealing with discrete Fourier transforms, you have to keep in mind that you...

14 years ago | 0