learn to Design software filters

Discussion in 'Embedded Systems and Microcontrollers' started by aamirali, Jul 29, 2014.

  1. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    Hi,

    I want to learn how to design software filters in embedded. I have two scenario's in it:

    a). sample a ac signal with freq of 50Hz. So I need to design a band pass filter which can only allow freq around 50hz to pass through, rest all must be rejected.

    b). sample a dc signal i.e zero freq. So design a low pass filter which only allow freq near 0 Hz to pass.



    1. I am not asking anyone to design these for me.
    2. I want to learn them how to do that it in microcontroller.
    3. I tried to search them on on internet but they all take to DSP & I couldn't understand the relationship. as it includes complex maths & no where i see link to microcontroller.
    4. After some searching I found this:
    http://coactionos.com/embedded design tips/2013/10/04/Tips-An-Easy-to-Use-Digital-Filter/

    5. Can someone point to weblink where I can learn like if have to design a filter in context of applying i in a microcontroller
    a). At what freq should I sample
    b). how many samples to take
    c). FIR or IIR, which will suit me?
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    It is not that simple. Understanding the math is a requirement. How are you going to debug a piece of code that does not produce the expected result. The code is the same weather you implement it in a DSP or a microcontroller. Deal with it!

    You also need to adjust your expectations. There is no way to construct a filter of any type with an infinitesimally small passband around a center frequency. The best you can do is attenuate frequency components in the stopband. IMHO web resources for learning filter design are basically crap. I recommend a college level textbook to learn how to specify and design filters.
     
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