I'd like to be able to use the symbolic toolbox for plotting the amplitude and phase response of a transfer function in the Laplace domain. Reason is because I find symbolic functions to keep my work neat and easily readable.
I've tried plotting the transfer functions' amp and phase characteristics using the following piece of code. Transfer function H describes a simple passive RC low pass filter where R*C = 0.001 in Vx = Vy + R*C*Vy*s.
H = 1/(0.001*s+1);
figure; fplot(abs(H), [0 100000]);
figure; fplot(angle(H), [0 100000]);
I would expect the phase shift between Vy and Vx to go from 0 to -pi/2 (or -90 deg), as in the bode plot below:
However, when plotting the angle with fplot I see no phase shift:
fplot(angle(H), [0 100000]);
I'd be glad if anyone could explain to me why bode and fplot give different results.
Thanks in advance!