genlfsrc.m

这是一个用于语音信号处理的工具箱

% genlfsrc.m

function [ps,dps]=genlfsrc(LF_ee,LF_tp,LF_te,LF_tc,LF_ta,pit_per)
% Generatevoicing source by LF model.

%       pit_per=101;LF_tc=58;LF_tp=41;LF_te=55;LF_ta=4;LF_ee=60;

	e0=0.0;ece=0.0;eps=0.0;alpha=0.0;wg=0.0;ps_1delay = 0.0;

	tc = pit_per*LF_tc/100.0;% % instant of closure from begining 
	tp = pit_per*LF_tp/100.0;% % instant of +ve peak from begining 
	te = pit_per*LF_te/100.0;% % instant of -ve peak from begining 
	ta = pit_per*LF_ta/1000.0;% slope constant of return phase 
	ee = LF_ee;              % desisred negative peak for excitation 
	ite = round(te);
	itc = round(tc);

% timing parameters 
	[e0,alpha,wg,eps,ece]=lfsrc(tc, tp, te, ta, ee);

% generate the differentiated waveform 
	for j=0:pit_per-1,
		if (j < ite) % opening phase 
			dug = e0*exp(alpha*(j+1))*sin(wg*(j+1));
		elseif (j < itc & ta ~= 0.0)  % closing phase 
			dug = -ee*(exp(-eps*((j+1)-ite))-ece)/(eps*ta);
 % if the numerical analysis methods do not converge properly, then there
 % may be cases when the area in the positive and the negative lobes of the
 % differentiated waveform does not go to zero. If the return phase values in
 % the differentiated waveform become positive then make them zero so that
 % the return phase is to zero. But if the return phase does not reach
 % zero value but remains negative then we cannot do anything about it.
 
			if (dug > 0.0)
				dug = 0.0;
			end
		else
			dug = 0.0;
		end
		dps(j+1) = dug;

% integrate the differentiated waveform to get the glottal pulse. 
		ps(j+1) = dug + ps_1delay;
		ps_1delay = ps(j+1);
		if (j >= ite & ps(j+1) < 0.0)
			ps(j+1) = 0.0;
		end
	end