Exponential transfer function

Hi,

I'd like to know how to input a transfer function in Matlab and plot the Frequency response (magnitude and phase).

My First problem is actually inputting the transfer function into Matlab,

It's the transfer function of a first order hold which is: [(1 + sT) / T] x [(1 - e^-sT) / s] x [(1 - e^-sT) / s]

How would I input this into Matlab? I've tried to use the tf() function but haven't got it right so far! - mainly because I don't know how to write exponents in a transfer function and also how to have it dependant on time period, T.

So far I was using this format: num = [1 0]; den = [1 1]; sys = tf(num, den)

But this only works with transfer function with simple 's' terms.

Anyone have any idea?

Thanks!

[Meet Doshi]

hd = exp(tf([-2 0],1))

Answer 1

[Paulo Silva]

Models with time delays