欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

粉红噪声matlab产生

程序员文章站 2022-07-01 10:56:07
...
function out = create_pink_noise(Fs, Sec, Amp)

% Creates a pink noise signal and saves it as a wav file
%
% Usage: create_noise(Fs, Sec, Amp);
%
%        Fs is the desired sampling rate
%        Sec is the duration of the signal in seconds
%        Amp is the amplitude in dB of the signal (0dB to -144dB)
%
% Author: sparafucile17 06/14/02

%error trapping
if((Amp > 0) || (Amp < -144))
    error('Amplitude is not within the range of 0dB to -144dB');
end

%Create Whitenoise
white_noise = randn((Fs*Sec)+1,1);

%Apply weighted sum of first order filters to approximate a -10dB/decade
%filter.  This is Paul Kellet's "refined" method (a.k.a instrumentation
%grade)  It is accurate to within +/-0.05dB above 9.2Hz
b=zeros(7,1);
for i=1:((Fs*Sec)+1)
    b(1) = 0.99886 * b(1) + white_noise(i) * 0.0555179;
    b(2) = 0.99332 * b(2) + white_noise(i) * 0.0750759;
    b(3) = 0.96900 * b(3) + white_noise(i) * 0.1538520;
    b(4) = 0.86650 * b(4) + white_noise(i) * 0.3104856;
    b(5) = 0.55000 * b(5) + white_noise(i) * 0.5329522;
    b(6) = -0.7616 * b(6) - white_noise(i) * 0.0168980;
    pink_noise(i) = b(1) + b(2) + b(3) + b(4) + b(5) + b(6) + b(7) + white_noise(i) * 0.5362;
    b(7) = white_noise(i) * 0.115926; 
end

%Normalize to +/- 1
if(abs(min(pink_noise)) > max(pink_noise))  
    pink_noise = pink_noise / abs(min(pink_noise));
else
    pink_noise = pink_noise / max(pink_noise);
end

%Normalize to prevent positive saturation (We can't represent +1.0)
pink_noise = pink_noise /abs(((2^31)-1)/(2^31));

%Scale signal to match desired level
pink_noise = pink_noise * 10^(Amp/20);

%Output noise signal
out = pink_noise(1:end-1);