音频处理Matlab程序

				function [b,a] = p_butt(Omegap,Omegas,Rp,As);
				% b=Ha(s)分子多项式系数
				% a=Ha(s)分母多项式系数
				% Omegap = 通带截止频率弧度/秒；Wp>0
				% Omegas = 阻带截止频率弧度/秒；Ws>Wp>0
				% Rp = 通带纹波 + dB；(Rp>0)
				% As = 阻带衰减 + dB；(As>0)
				
				if Omegap 				    error('通带截止频率必须大于0')
				end
				if Omegas 				    error('阻带截止频率必须大于通带截止频率')
				end
				if(Rp 				    error('通带纹波和阻带衰减必须大于0')
				end
				N = ceil((log10((10^(Rp/10)-1)/(10^(As/10)-1)))/(2*log10(Omegap/Omegas)));
				fprintf('\n***巴特沃斯滤波器阶次=%2.0f\n',N)
				OmegaC = Omegap/((10^(Rp/10)-1)^(1/(2*N)));
				[b,a]=un_buttap(N,OmegaC);