改进的过零检测法的matlab程序

clear;
clc;
f1=[5 10 15 20 28 33 40 48 53 58];
fs=400;
det=1/400;
t=0:det:2-det;
N=length（t）;
for j=1:1:10
y1=（5.738*10^（-5）*f1（j）*f1（j）+0.002*randn（1N））.*sin（2*pi*f1（j）*t+pi/3）+0.016*sin（2*pi*50*t+pi/4）+（（5.738*10^（-5）*f1（j）*f1（j）+0.002*randn（1N））/10）.*sin（2*pi*3*f1（j）*t+pi/3）+1.525*10^（-5）*f1（j）*f1（j）*randn（1N）;
%y1=sin（2*pi*f1（j）*t+pi/3）;
%y1=[0.15546875	0.190917969	0.126464844	0.1296875	0.107128906	-0.0765625	-0.189355469	-0.176464844	-0.237695313	-0.066894531 -0.086230469	0.15546875	0.149023438	0.297265625	0.107128906	0.116796875	-0.008886719	-0.269921875	-0.131347656	-0.057226562 -0.057226562	0.068457031	0.081347656	0.097460937	0.039453125	0.15546875	-0.002441406	-0.147460938	-0.137792969	-0.092675781 -0.025	-0.002441406	0.110351563	0.055566406	0.078125	-0.008886719	-0.0