吹管音樂濾波去噪使用雙線性變換法設(shè)計切比雪夫ii型濾波器-資料下載頁
2025-01-18 15:51本頁面
【正文】 原始吹管音樂幅度譜圖39。)。gridaxis([0,4*10^3,0,2000])subplot(3,2,3)。plot(t,y)。xlabel(39。時間(單位:s)39。)。ylabel(39。幅度39。)。title(39。加噪后的吹管音樂39。)。gridsubplot(3,2,4)。plot(f,Y)。xlabel(39。頻率(單位:Hz)39。)。ylabel(39。幅度譜39。)。title(39。加噪后的吹管音樂幅度譜圖39。)。gridaxis([0,4*10^3,0,2000])subplot(3,2,5)。plot(t,y_fil)。xlabel(39。時間(單位:s)39。)。ylabel(39。幅度39。)。title(39。濾波后的吹管音樂39。)。gridaxis([0,3,1,1])subplot(3,2,6)。plot(f,Y_fil)。xlabel(39。頻率(單位:Hz)39。)。ylabel(39。幅度譜39。)。title(39。濾波后的吹管音樂幅度譜圖39。)。gridaxis([0,4*10^3,0,2000])figuresubplot(211)。plot(f,20*log10(abs(Y)/max(abs(X))))。axis tight。grid on。% 繪制加噪吹管音樂頻譜圖subplot(212)。plot(f,20*log10(abs(Y_fil)/max(abs(X))))。axis tight。grid on。% 繪制去噪吹管音樂頻譜圖sound(y_fil,fs,bits)。附錄二：afd_chb2函數(shù)function [b,a] = afd_chb2(Wp,Ws,Rp,As)。% Analog Lowpass Filter Design: Chebyshev2% % [b,a] = afd_chb2(Wp,Ws,Rp,As)。% b = Numerator coefficients of Ha(s)% a = Denominator coefficients of Ha(s)% Wp = Passband edge frequency in rad/sec。 Wp 0% Ws = Stopband edge frequency in rad/sec。 Ws Wp 0% Rp = Passband ripple in +dB。 (Rp 0)% As = Stopband attenuation in +dB。 (As 0)%if Wp = 0 error(39。Passband edge must be larger than 039。)endif Ws = Wp error(39。Stopband edge must be larger than Passband edge39。)endif (Rp = 0) | (As 0) error(39。PB ripple and/or SB attenuation ust be larger than 039。)endep = sqrt(10^(Rp/10)1)。A = 10^(As/20)。OmegaC = Wp。OmegaR = Ws/Wp。g = sqrt(A*A1)/ep。N = ceil(log10(g+sqrt(g*g1))/log10(OmegaR+sqrt(OmegaR*OmegaR1)))。fprintf(39。\n*** Chebyshev2 Filter Order = % \n39。,N)[b,a]=u_chb2ap(N,As,Ws)。附錄三：function [db,mag,pha,grd,w] = freqz_m(b,a)。% freqz 子程序的改進(jìn)版本% % [db,mag,pha,grd,w] = freqz_m(b,a)。% db = [0 到pi弧度]區(qū)間內(nèi)的相對振幅(db)% mag = [0 到pi弧度]區(qū)間內(nèi)的絕對振幅% pha = [0 到pi弧度]區(qū)間內(nèi)的相位響應(yīng)% grd = [0 到pi弧度]區(qū)間內(nèi)的群遲延% w = [0 到pi弧度]區(qū)間內(nèi)的501個頻率樣本向量% b = Ha(z)的分子多項式系數(shù)(對FIR b=h)% a = Ha(z)的分母多項式系數(shù)(對 FIR: a=[1])%[H,w] = freqz(b,a,1000,39。whole39。)。 H = (H(1:1:501))39。 w = (w(1:1:501))39。 mag = abs(H)。 db = 20*log10((mag+eps)/max(mag))。 pha = angle(H)。% pha = unwrap(angle(H))。 grd = grpdelay(b,a,w)。% grd = diff(pha)。% grd = [grd(1) grd]。% grd = [0 grd(1:1:500)。 grd。 grd(2:1:501) 0]。% grd = median(grd)*500/pi。
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