RCL lowpass design

Discussion in 'Homework Help' started by Homie, Nov 15, 2007.

  1. Homie

    Thread Starter New Member

    Nov 15, 2007
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    Hi there, i need help with the methode of designing a RCL lowpass filter. I know the -3dB frequency 70MHz and i know the quality factor 0,7. But i just forgot how to get started and what formulas to use :(
    Thomas
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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  3. Homie

    Thread Starter New Member

    Nov 15, 2007
    3
    0
    Yea thanks ive red that, but i just forgot what to do first. I have the transfer function for the filter, and i know the wo(2*pi*70000000) and Q(0,7) but what do i do first?? I cant remember if i have to match the impedans of the filter with the rest of the circuuit and/or what other things i have to consider.
     
  4. Homie

    Thread Starter New Member

    Nov 15, 2007
    3
    0
    Now i think ive founded my components for my filter. But but i have som difficulties understanding my simulations. Because i keep getting +db in the low frequencies and my aim was to get 0db in dc gain. And when i look at the formula for the lowpass filter, the nominator is 1/LC. Can anybody tell me what im doing wrong??
     
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