step input

Discussion in 'Homework Help' started by jstrike21, Jan 28, 2010.

  1. jstrike21

    Thread Starter Member

    Sep 24, 2009
    Problem 1. A system has a transfer function with no zeros, a single pole at s = -6, and a dc gain of 9.
    a) Write the transfer function
    b) Determine the response to a step of 5u(t). Assume the output prior to t =0 is 0.

    I got the transfer function as T(s)=54/(s+6)

    I'm just confused on what it means by step of 5u(t), could use a little direction
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    The step 5u(t) is simply a driving function whose value is zero for t<0 and 5 for t>=0. It's a well-known notation for a step function. The u sometimes has a -1 subscript.

    When transformed to the 's' domain u(t)<=>1/s

    So K*u(t)<=>K/s