jens
1f5b0b0570
git-svn-id: http://moon:8086/svn/matlab/trunk@128 801c6759-fa7c-4059-a304-17956f83a07c
30 lines
610 B
Matlab
30 lines
610 B
Matlab
function [B,A] = boost2(fs, fc, bw, gain);
|
|
%BOOST - Design a boost filter at given gain, center
|
|
% frequency fc, bandwidth bw, and sampling rate fs
|
|
% (default = 1).
|
|
%
|
|
% Cookbook formulae for audio EQ biquad filter coefficients
|
|
% by Robert Bristow-Johnson <rbj@audioimagination.com>
|
|
|
|
Q = fs/bw;
|
|
w0 = 2*pi*fc/fs;
|
|
|
|
A=sqrt(gain);
|
|
alpha = sin(w0)/(2*Q)
|
|
|
|
b0 = 1 + alpha*A
|
|
b1 = -2*cos(w0)
|
|
b2 = 1 - alpha*A
|
|
a0 = 1 + alpha/A
|
|
a1 = -2*cos(w0)
|
|
a2 = 1 - alpha/A
|
|
|
|
A = [a0 a1 a2] / a0;
|
|
B = [b0 b1 b2] / a0;
|
|
|
|
if nargout==0
|
|
freqz(B,A);
|
|
title('Boost Frequency Response')
|
|
end
|
|
|