1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

FIR Filter

  1. Nov 3, 2013 #1
    1. The problem statement, all variables and given/known data

    Consider the FIR filter with {bk} = {3, 4, -4, -3}. These are the filter coefficients for k = 0, 1, 2, and 3, respectively. Sketch the output y[n] where the input is:

    x[n] = δ[n]
    x[n] = (u[n] - u[n-2])
    x[n] - u[n]

    2. Relevant equations

    [itex]\sum^{M}_{k=0}b_k x[n-k][/itex]

    3. The attempt at a solution

    I am not sure how to process this form.
    I would build a table

    for the first one x[0] = 3, x[2] = 4, etc..
    for second x[0] = 3,..., x[3]=(3-4) = -1

    I my notes don't have anything with u[n]
  2. jcsd
  3. Nov 4, 2013 #2


    User Avatar
    Homework Helper
    Gold Member

    That's the right idea, with the exception of: don't you mean " y[0] = 3, y[1] = 4. etc.."? (As opposed to x[0] = 3, x[2] = 4?)

    I don't think that's quite right.

    u[n] is the unit step function.
    u[n] =
    1 & \text{if } n \geq 0 \\
    0 & \text{if } n < 0

    I suggest making a table giving u[n] as a function of n, for n = -1 to around 7 or so. Then do the same thing for -u[n-2]. Then again for u[n] - u[n-2]. And finally make another table for y[n] with that input.
    Last edited: Nov 4, 2013
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: FIR Filter