digital filter

Discussion in 'Embedded Systems and Microcontrollers' started by mik3, Jun 1, 2008.

  1. mik3

    Thread Starter Senior Member

    Feb 4, 2008
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    Hello guys,

    I want to read an analogue audio signal with a microcontroller and filter it digitally (by writing the proper algorithm). Any ideas on how to implement a bandpass digital filter?
     
  2. Papabravo

    Expert

    Feb 24, 2006
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  3. hgmjr

    Moderator

    Jan 28, 2005
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  4. mik3

    Thread Starter Senior Member

    Feb 4, 2008
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    Thanks for the links but do you know any transfer function which makes the function of a bandpass filter?
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    You select a low pass function for one end of the pass band, and a high pass for the other. The low pass rolls off the upper end of the band; the high pass rolls off the lower end. The range of frequencies between the -3 dB points is the passband.
     
  6. mik3

    Thread Starter Senior Member

    Feb 4, 2008
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    Yes but i have never built a digital filter before so i would like to know how we get the transfer function of a low pass filter for example according to the cutoff frequency, the Q factor etc we want.
     
  7. Caveman

    Active Member

    Apr 15, 2008
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  8. mik3

    Thread Starter Senior Member

    Feb 4, 2008
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    Thanks Caveman
     
  9. roddefig

    Active Member

    Apr 29, 2008
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    If you have access to the Filter Design Toolbox in MATLAB I would highly recommend fdatool. Otherwise, Filter Free is my favorite analog filter design tool that also does digital filter design. It's available for download from http://www.filter-solutions.com/
     
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