IMPULSE AND STEP RESPONSE

I know that 'stepz' and 'impz' can be used to find the step and impulse response of a digital filter when numerator and denominator coefficients are given as arguments. How I can I find the above responses for a continuos time system using the numerator and denominator coefficients? Please clarify

Answer 1

[Richard Zappulla]

Hi,

Quite simply, you can use the step() and impulse() commands given a continuous-time system. The inputs to these commands is a transfer function generated using the tf(numerator_coeffs, denomenator_coeffs). If you do not specify an output to these functions, they will generate a plot with impulse or step response respectively. If you specify an output, then it is left you to plot the results.

I would encourage you to review the help files for each command, but below is a code snippet to get you going.

 transFcn = tf([1], [1,1]) % Transfer function for the system 1/(s+1)
 impulse(transFcn);              % Generates impulse response
 [y, t] = step(transFcn);        % Generates response and time
 figure(1), clf, plot(t, y), xlabel('Time'), ylabel('Response'), title('Step Response');

Hope this helps!

EDIT: swapped arguments in the plot() fcn call to match axis labels

[Ananthu S]

Thanks for the information. I think step(b,a) also works. I got same answers when I tried both the methods.

Answer 2

[Girma]

 transFcn = tf([1], [1,1]) % Transfer function for the system 1/(s+1)
 impulse(transFcn);              % Generates impulse response
 [y, t] = step(transFcn);        % Generates response and time
 figure(1), clf, plot(t, y), xlabel('Time'), ylabel('Response'), title('Step Response');