This was the first experiment performed in Scilab. Scilab is an open source software designed for doing complex computations using simpler functions.We had to design Butterworth digital filter from from analog Butterworth filter by passing inputs like - Stop band attenuation(As), Pass band attenuation(Ap) , Pass band frequency(wp) & Stop band frequency(ws). Filter order and cut off frequency was then calculated.
Normalized transfer function of LPF was obtained, which was then converted into denormalized transfer function of desired(LPF or HPF) filter.The response in z -domain is equivalently calculated by IIM or BLT transformations.
Frequency Response of Butterworth Filter is maximally flat - monotonically decreasing in Pass band & Stop band. Steepness of the response depends upon order of the filter
In BLT, Analog frequency in the range [ 0 to infinity) is compressed to Digital frequency in the range [ 0 to pie ]. This frequency compression is called frequency warping which is used in the design procedure of IIR filter design when BLT method is used.
ReplyDeleteTransition width of Butterworth filter is high compared to chebyshev filter
ReplyDeleteThe entire algorithm is well explained. Butterworth filters are used for critical applications due to higher order and maximally flat pass band.
ReplyDeleteYes, due to their higher orders, they are difficult to implement practically
DeleteButterworth filters are monotonic in both pass band as well as stop band.
ReplyDeleteThey require more hardware components for realization
ReplyDeleteit 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
ReplyDeleteWe have to input parameters such as Ap,As,stop band and pass band frequency when we execute the scilab code
ReplyDeleteThe order of the filter increases as the transition width of the filter decreases. In butterworth filter there is no ripple in stopband as well as in passband
ReplyDeleteDoes it have ripple pass band and stop band ?
ReplyDeleteAlso, state the advantages of IIR filters ?
ReplyDeleteThere are no ripples either in passband or stop band. Further they require less hardware and thus memory
ReplyDelete