butterworthpoles.html

syntfil[ButterworthPoles] - compute the poles for the transfer function of the Butterworth approximation

Calling sequence:

ButterworthPoles(order, Os, ap)

Parameters:

order - order of the Butterworth approximation [-]

Os - stopband frequency of normalized lowpass (NLP) [1/s]

ap - passband ripple [dB]

Parameter order must be positive integer. Parameter ap must be positive number. Parameter Os is not utilized and its type is not checked.

Description:

This function returns leading coefficient of the denominator polynomial of transfer function and one dimensional array of transfer function's poles.

Count of the poles is given by order parameter.

Info level:

Setting of variable infolevel[syntfil] can be used to get more detailed results.

infolevel[syntfil] =

2 - print leading coefficient of denominator polynomial of transfer function and one dimensional array of transfer function's poles on separate lines with description

3 - as level 2 + print parameter .

Example:

> with(syntfil):

> infolevel[syntfil]:=3;

> ButterworthPoles(5,2,3);

epsilon = .9976283451

ButterworthPoles:

Gc = .9976283451

Poles = [-.8094012830+.5880644545*j, -.8094012830-.5880644545*j, -.3091637790+.9515082750*j, -.3091637790-.9515082750*j, -1.000475007]

> infolevel[syntfil]:=1;

> ButterworthPoles(4,2,3);

See also:

ButterworthNLPOrder

Butterworth, Butterworth_asnew

NLP2LP, NLP2HP, NLP2BP, NLP2BP2, NLP2BS, BodePlot

in addition to Butterworth approximation the following approximations can be used
ChebyshevPoles, InvChebyschevPolesZeros, InvChebyshevBPolesZeros, CauerPolesZeros, CauerBPolesZeros, CauerCPolesZeros