joint_map.m

这个MATLAB程序是用于对音频信号进行降噪处理

function H = joint_map(gamma,xihat)
% JOINT_MAP - Joint MAP spectral estimation (Wolfe and Godsill, 2001) 
%    H = JOINT_MAP(GAMMA,XIHAT) returns the joint MAP spectral amplitude
%    and phase estimation filter H given a posteriori signal-to-noise ratio 
%    (SNR) GAMMA and an estimate XIHAT of a priori SNR.  GAMMA and XIHAT 
%    may be arrays but must be of equal dimension.
%
% References:
% 
% P. J. Wolfe and S. J. Godsill. Simple alternatives to the Ephraim and
% Malah suppression rule for speech enhancement. In Proc. IEEE Workshop on 
% Statistical Signal Processing, pages 496-499, August 2001.

% Author: Patrick J. Wolfe
%         Signal Processing Group
%         Cambridge University Engineering Department
%         [e-mail]
%
% Copyright (c) 2001 by Patrick J. Wolfe
% $Revision: 1.2 $  $Date: 2001/01/24 13:09:23 $

% Joint MAP spectral estimation filter calculation
%
upsilon = gamma.*xihat./(1+xihat);
H = (xihat+sqrt(xihat.^2+2.*(1+xihat).*(xihat./gamma)))./(2.*(1+xihat));