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Filters... why passive implementations are odd?

  • 27-10-2014 09:16PM
    #1
    arctan
    Closed Accounts Posts: 354 ✭✭


    So ... why are passive implementations always odd and active are even?


Comments

  • #2
    knickerbocker
    Registered Users, Registered Users 2 Posts: 238 ✭✭knickerbocker


    Phase baby, phase.


  • #3
    arctan
    Closed Accounts Posts: 354 ✭✭arctan


    can I ask for an expansion on that? :-)

    Particularly butterworth passive... is it that phase is not distorted much in the passband, but goes bananas in the stopband, if odd?


  • #4
    knickerbocker
    Registered Users, Registered Users 2 Posts: 238 ✭✭knickerbocker


    You'll get a 90 degree shift in phase per order, not sure what you mean by going bananas in the stop band?
    What frequency are you passing?
    Do you have a circuit with values and measured results....... distortion maybe being caused by the components your using.


  • #5
    arctan
    Closed Accounts Posts: 354 ✭✭arctan


    I have a 5th order butterworth lpf, it's all theoretical.
    I just don't fully understand the reasoning as to why active implenetations are usually in even orders, where passive are usually in odd.


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