Stone Studio

Moving average filter
To compute an N-sample moving average of x with zero padding:
y=filter(ones(N,1)/N,1,x);
For large N, it is faster to use

x = [1:0.2:4]‘;
N = 5;
windowSize = 5;
y1 = filter(ones(1,N)/N,1,x);

y2=cumsum(x)/N;
y2(N+1:end)=y2(N+1:end) – y2(1:end-N);

Locating zero-crossings and extrema
To obtain the indices where signal x crosses zero:

i=find(diff(sign(x))); % The kth zero crossing lies between x(i(k)) and x(i(k)+1)

Linear interpolation [...]

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The find command is used to locate files on a Unix or Linux system. find will search any set of directories you specify for files that match the supplied search criteria. You can search for files by name, owner, group, type, permissions, date, and other criteria. The search is recursive in that [...]

I love LaTeX. It’s my preferred tool whenever I need to write a document in English. But it had one little problem: The documents it generated, even though beautifully typeset, had an academic look. For someone who submits the documents to hitec companies, an engineering-like look was more appealing.
So I wrote my own document [...]

Python has matured to the point where it is a very powerful computational environment with flexibility that is unmatched by any commercial product. But this flexibility comes at the cost of a very fragmented install procedure. The default installation of python is feature poor and the needed features for computations are spread out over many [...]

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I’m using CodeColorer for my WordPress, it is the plug in which allows you to insert code snippets into the post with nice syntax highlighting. It uses [ cc lang="matlab"] MatlabCode [ /cc ] syntax. I found a plug in available in Windows Live Writer, I am now be able to just highlight a line [...]

This page describes some basic sound processing functions in MATLAB. We’ll begin by reading in a wav file. You can download it here 440_sine.wav it contains a complex tone with a 440 Hz fundamental frequency (F0) plus noise.