Monday, 3 April 2017

Butterworth Filter Design

The task was to design a digital Butterworth filter from an analog filter and with the help of input specifications. Scilab software was used to code and observe the output plot with frequency on x axis and attenuation (in db) on Y axis.2 cases were studied, one with the low pass filter and other with the high pass design.The pass band and stop band attenuation values which were fed in the code were later verified with the help of graph for the corresponding analog pass band and stop band frequencies respectively.From the pole zero plot observed in scilab we saw that in case of digital LPF ,poles lay inside the unit circle, thus the digital filter was stable in nature.

10 comments:

  1. There is no ripple in stopband and passband.

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    1. Frequency Response of Butterworth Filter is maximally flat - monotonically decreasing in Pass band & Stop band.

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    2. Frequency Response of Butterworth Filter is maximally flat - monotonically decreasing in Pass band & Stop band.

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  2. Transition width is high when compared with chebyshev filter

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  3. Scilab is really helpful in debugging the problem in logic

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  4. It is good for filters that have order1

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  5. IIM and BLT methods are used for designing butterworth filter.

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  6. it is also referred as a maximally flat magnitude filter. The rate of falloff response of the filter is determined by the number of poles taken in the circuit

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  7. Butterworth filters are hard to implement

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  8. It is characterized by lack of ripples in the magnitude response

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