computefft.m

是“MATLAB混合编程与工程应用”一书的源码

function [fftData, freq, powerSpect] = ComputeFFT(data, interval)
%COMPUTEFFT Computes the FFT and power spectral density of the input data.
%   [FFTDATA, FREQ, POWERSPECT] = COMPUTEFFT(DATA, INTERVAL)
%   Computes the FFT and power spectral density of the input data.
%   This file is used as an example for the .NET Builder
%   Language product.

%   Copyright 2001-2005 The MathWorks, Inc.
%   $Revision: 1.1.10.1 $  $Date: 2005/12/22 17:57:55 $

    if (isempty(data))
        fftdata = [];
        freq = [];
        powerspect = [];
        return;
    end
    if (interval <= 0)
        error('Sampling interval must be greater then zero');
        return;
    end
    fftData = fft(data);
    freq = (0:length(fftData)-1)/(length(fftData)*interval);
    powerSpect = abs(fftData)/(sqrt(length(fftData)));