Question

matlab keep ignoring negative values when i plot the data....

what should i do to plot negative numbers...

Answer 1

Here is one of the example to plot the negative value, I used "axis" function.

tt = -0.00025:0.00001:0.00025;// setting the time axis
y1 = 20*cos(2*pi*(2000)*(tt -37.2/10));//one of the function

tt = -0.00025:0.00001:0.00025;// setting the time axis

y2 = 14*cos(2*pi*(4000)*(tt +41.3/10));//

y3= y1+y2;//An operation on signal

subplot(3,1,1)
plot(tt,y1)
title('Y1')
xlabel('Time')
axis([min(tt) max(tt)    ylim])

subplot(3,1,2)
plot(tt,y2)
title('Y2')
xlabel('Time')
axis([min(tt) max(tt)    ylim])

subplot(3,1,3)
plot(tt,y3)
title('Y3')
xlabel('Time')
axis([min(tt) max(tt)    ylim])