fig3_11.m

数字信号处理Matlab演示文件,其中各个文件加放置了不同的matlab子文件

%	Figure 3.11
%	BM
%	August 98


clear
clf
colordef(1,'black')

subplot(121)
rmax = +1;
rmin = -3;
imax = +4;
imin = -imax;
axis( [ rmin rmax imin imax ] );
hold on
axis('square')
title('s-plane')
xlabel('real')
ylabel('imag')
grid

subplot(122)
Tmax = 5;
dt = 0.001;
T = 0:dt:Tmax;
axis( [0 Tmax -2 +2] )
title('impulse response')
xlabel('time')
ylabel('h(t)')
hold on

fprintf(1,'Figure 3.11: Impulse response & pole postion.\n');
fprintf(1,'           : Left mouse button places pole in s-plane at crosshair.\n');
fprintf(1,'           : Right mouse button for final placement.\n');


subplot(121)
[x,y] = ginput(1);
if x > rmax, x = rmax, end;
if x < rmin, x = rmin, end;
if y > imax, y = imax, end;
if y < imin, y = imin, end;
l1 = line('Xdata',x,'Ydata',y,'Marker','x','Color','y','EraseMode','xor');
l2 = line('Xdata',x,'Ydata',-y,'Marker','x','Color','y','EraseMode','xor');


subplot(122)
den = poly([x+j*y x-j*y]);
num = [ 1 -x ];
[YY,XX] = impulse(num,den,T);
env = exp(x*T);
l3 = line('Xdata',T,'Ydata',YY(:,1),'LineStyle','-','Color','y','EraseMode','xor');
l4 = line('Xdata',T,'Ydata',env,'LineStyle',':','Color','b','EraseMode','xor');
l5 = line('Xdata',T,'Ydata',-env,'LineStyle',':','Color','b','EraseMode','xor');


but = 1;
while but == 1
	subplot(121)
	[x,y,but] = ginput(1);
	if x > rmax, x = rmax; end;
	if x < rmin, x = rmin; end;
	if y > imax, y = imax; end;
	if y < imin, y = imin; end;
	set(l1,'Xdata',x,'Ydata',y);
	set(l2,'Xdata',x,'Ydata',-y);

	subplot(122)
	den = poly([x+j*y x-j*y]);
	num = [ 1 -x ];
	[YY,XX] = impulse(num,den,T);
	env = exp(x*T);
	set(l3,'Xdata',T,'Ydata',YY(:,1));
	set(l4,'Xdata',T,'Ydata',env);
	set(l5,'Xdata',T,'Ydata',-env);
end