Respondida
I have a sine wave whose frequency is changing in irergular intervals from 50HZ to 55HZ and back to 50HZ.i need to extract the frequency information from the sin wave I need to plot the frequency vs time in a graph..
In this simple example, you can use the short-time Fourier transform to do this. You're really after something called the instan...

alrededor de 14 años hace | 0

| aceptada

Respondida
Small variation in amplitude
Just multiply the signal by a constant between 0 and 1 t = linspace(0,1,1000); x = cos(2*pi*100*t)+sin(2*pi*100*(t...

alrededor de 14 años hace | 0

Respondida
function acts differently in command window to when its run in a .m file.
What is getFileName returning? We need to know what that looks like For example, if you run it from the command line >>f...

alrededor de 14 años hace | 0

Respondida
Continuous Time Fourier Transform of a signal matrix
You stated in your original post that your matrix had an even number of elements, 100x2. In fact your matrix is 9079x2. You data...

alrededor de 14 años hace | 1

Respondida
Newbie: How to create a low pass that can be exported into c++?
Which MathWorks' products do you have? If you have MATLAB Coder, the Signal Processing Toolbox, and the DSP System Toolbox, you ...

alrededor de 14 años hace | 0

Respondida
Continuous Time Fourier Transform of a signal matrix
If the first column of your matrix is just the time vector with increments of 0.02 seconds, then just take the Fourier transform...

alrededor de 14 años hace | 0

| aceptada

Respondida
matlab error! "must return a column vector."
You don't help us to help you when you post a function that will not run like the one you have posted: function n_loss = F...

alrededor de 14 años hace | 0

Respondida
reading text file to matlab
Are the file names such that there is 1 per line in the text file? If so, the following works for me. I've just changed your ...

alrededor de 14 años hace | 0

| aceptada

Respondida
Is this a legal Matlab reseller?
I think you should contact MathWorks to determine which companies are authorized to sell MathWorks' products.

alrededor de 14 años hace | 0

Respondida
Size of Images varying
The Image Processing Toolbox has medfilt2

alrededor de 14 años hace | 0

Respondida
Autoregressive model using Yule-Walker method
You have to specify the order. One thing you can do is to specify a high order and return the reflection coefficients. The negat...

alrededor de 14 años hace | 0

Respondida
2D Matlab Plot help please
The x and y variables must have the same length. What relationship is there between xdata and Revs?

alrededor de 14 años hace | 0

Respondida
finding average of a percentile of rows in a matrix?
Assume A is your matrix. numrows = round(0.2*size(A,1)); lastrowstart = size(A,1)-numrows+1; lowermean = mean(A(1:num...

alrededor de 14 años hace | 0

Respondida
error using unique function
Is it a cell array of numeric values? You can use cell2mat() A = {1 5 9 ; 2 3 4; 2 4 5}; B = unique(cell2mat(A(:,1)))...

alrededor de 14 años hace | 1

Respondida
Minute error in array causes == to be ineffective
Hi Elliot, this is a reality of dealing with floating point numbers. You could use a tolerance a = randn(10,1); for ii =...

alrededor de 14 años hace | 0

| aceptada

Respondida
KB1 = conv2(b,Ksigma,'same')
When you convolve two matrices (images) of different sizes you get an output image that has row dimension equal to the sum of th...

alrededor de 14 años hace | 0

Respondida
How to interpolate a value between two values in an array?
Have you tried interp1? For example: t = 0:10; x = sin(t); tnew = 0:.25:10; xnew = interp1(t,x,tnew); plo...

alrededor de 14 años hace | 0

Respondida
how to do digital filter on this EEG data
I think Honglei has given you good advice. And I do think you should consider downsampling your data with decimate.m, or resampl...

alrededor de 14 años hace | 0

Respondida
How can I use the function 'affyread' in standalone applications?
Hi Prasanth, the function affyread is not supported by the compiler. You can see that here: <http://www.mathworks.com/product...

alrededor de 14 años hace | 1

| aceptada

Respondida
got an error "index exceed matrix dimension"
I think you should determine where the error is occurring. In other words, if you remove this for loop: for i=1:530 ...

alrededor de 14 años hace | 0

Respondida
changing the string "JF 2009" to two seperate strings "J 2009" " F2009"
One way: Amodified = A; B = char(A(:,3)); B(:,2) = []; B = cellstr(B); Amodified(:,3) = B;

alrededor de 14 años hace | 0

Respondida
MY QUESTION IS I WANT TO FIND THE MAXIMUM NO. FROM GIVEN DATA SET USING MATLAB CODE.
x = randn(1000,1); [maxval,I] = max(x); maxval gives the maximum value and I gives which element of the vector that maxi...

alrededor de 14 años hace | 0

Respondida
convolution of 2 sequestions
That depends on the structure of your text file. If it is a simple .txt file of numbers, you can just use load(), or dlmread(). ...

alrededor de 14 años hace | 0

Respondida
Defining a for loop
It depends on the range of your t variable and how finely you want to represent that. If 0<=t<=1, then you can't represent it...

alrededor de 14 años hace | 0

Respondida
Anyone can teach me about SSIM.m?
Have you read the paper and worked through the demos on the authors' website? <http://www.ece.uwaterloo.ca/~z70wang/research/...

alrededor de 14 años hace | 0

Respondida
visualize trend of temperature and rainfall data in matlab
If you want to use the scaling coefficients from a wavelet decomposition, then use wavedec() followed by wrcoef() with the 'a' o...

alrededor de 14 años hace | 0

Respondida
How accrues the delay in mfilt.firsrc ?
Hi Stef, you can find that by hm = mfilt.firsrc(l,m); mean(grpdelay(hm))/m % now start the output signal at 12+1 y...

alrededor de 14 años hace | 0

| aceptada

Respondida
Is there a function in matlab that finds a transmition function of a filter, based on the input and output signals?
You can use tfestimate() in the Signal Processing Toolbox to estimate the transfer function. In the System Identification Too...

alrededor de 14 años hace | 0

Respondida
My signal level is strange.
It looks like you are just implementing this difference equation A = [1 -2 1]; B = [1 0 0 0 0 -2 0 0 0 0 0 1]; y = fil...

alrededor de 14 años hace | 0

Respondida
Create a 4-pole, 300-6000HZ bandpass butterworth filter?
If you want 4 poles and you have a bandpass filter, then you have to specify the order as 2. Also to convert from normalized fre...

alrededor de 14 años hace | 0

| aceptada