1. We will be in Read Only mode (no new threads, replies, registration) starting at 9:00 EDT for a number of hours as we migrate the forums to upgraded software.

Filter Design

Discussion in 'Homework Help' started by roxetz, Mar 6, 2006.

  1. roxetz

    Thread Starter New Member

    Mar 6, 2006
    I need to deisgn a filter that recovers a 40kHz signal in a very noisy system. I think I would need to implement a bandpass filter for this, with passband omega_o = 80pi rad/s. However, I think I need more information to find out the circuit elements/bandwidth/quality factor/cutoff frequencies. Any ideas would be greatly appreciated. ASAP PLEASE! Thanks.
  2. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    Sounds awefully much like your are dealing with ultrasonic transducers. I had a similar problem a few years ago and ended up making an active filter using an OP AMP. Unfortunately I don't think I still have this circuit but I will look for it tomorrow. I know we had one hell of a time trying to get it working but in the end it worked well.
  3. Papabravo


    Feb 24, 2006
    An accessible reference for passive filter design is the Radio Amateurs Handbook. It is published by the American Radio Relay League(ARRL)
    ARRL website
    It has tables for Butterworth, Chebychef, and Bessel up to 8th order.
    You might be surprised by the size of the components that you need: especially the inductors.

    Good Luck
  4. hgmjr

    Retired Moderator

    Jan 28, 2005
    Give this website a look.

    Filter Design Tool

  5. roxetz

    Thread Starter New Member

    Mar 6, 2006
    Thanks guys. I know how to do this now...