f2=1/200;
f3=0.2:0.2:1/f2;
x2=0.1:0.1:100;
N1=1000;
Y=sin(2*pi*x2*f2);
Y1=fft(Y,N1);
Y2=abs(Y1);
Y5=angle(Y1);
YY=Y5*pi/180;
YY1=(YY-90)*180/pi;
Y3=Y2*2 / N1;
Y4=Y2*1;
Y11 = Y4.*cos(YY1)+Y4.*sin(YY1).*1i;
Y111=ifft(Y11,N1);
Y1111=abs(Y111);
subplot(3,3,6);
plot(f3,Y111);
subplot(3,3,7);
plot(f3,Y3);
subplot(3,3,8);
plot(f3,Y);