Converting Transfer Function to T-Domain | Matlab Plot Help Needed

[khedira]

i need to convert my transfer function to t-domain format and then plot the graph of the equivalent t-domain equation. i am using the ilaplace function to convert the s-domain transfer function to the t-domain equation.

my code is

>> f = (s + 3.1)/(s^2 +3.1*s + 2.23)

f = (s+31/10)/(s^2+31/10*s+223/100)

>> a = ilaplace(f)

a = (1/2-31/138*69^(1/2))*exp(-1/20*(69^(1/2)+31)*t)+(1/2+31/138*69^(1/2))*exp(1/20*(-31+69^(1/2))*t)

>> plot(a)
? Error using ===> plot
Conversion to double from sym is not possible.

May i know how can i plot the graph of the transfer function in t-domain? Any advise is appreciated. Thank you!

 

[╔(σ_σ)╝]

First of all, you never gave the range of t for the plot.
Secondly,(if I recall correctly) you should write plot(t,a(t)) not plot(a).

 

[khedira]

First of all, you never gave the range of t for the plot.
Secondly,(if I recall correctly) you should write plot(t,a(t)) not plot(a).

yes, you are right, i declared a range for t and it's working. Thank you.