i kind want to pull the blue curve forward in time to match the red curve , so that the peaks match in time. that is the marker curve should be moved 20 seconds forward.

Answer 1

[Star Strider]

Just add (or subtract) 20 seconds from the blue curve time value, then plot them together.

A simple example:

xr = 1:20;
yr = sin(2*pi*xr/10);
xb = 1:25;
yb = cos(2*pi*xb/10);

figure
subplot(2,1,1)                                  % Original
plot(xr, yr, 'r')
hold on
plot(xb, yb, 'b')
grid
subplot(2,1,2)                                  % Shifted
plot(xr, yr, 'r')
hold on
plot(xb+2.5, yb, 'b')
grid

The finddelay function can also be helpful here.

.