syntfil[ButterworthNLPOrder] - compute the order of the Butterworth approximation of the normalized lowpass (NLP) filter
Calling sequence:
ButterworthNLPOrder(Os, ap, as)
Parameters:
Os - stopband frequency of NLP [1/s]
ap - passband ripple [dB]
as - stopband attenuation [dB]
All parameters must be positive real values, where Os > 1 and ap < as .
Description:
order - order of the Butterworth approxiamation [-]
ap - passband ripple [dB]
as - stopband attenuation [dB]
Info level:
Setting of variable infolevel[syntfil] can be used to get more detailed results.
infolevel[syntfil] =
2 - print output of function (order, Os, ap)
3 - as level 2 + print secondary parameters of NLP (epsilon, k, k1)
Example:
> | with(syntfil): |
NLP specification
> | Os,ap,as:=2,3,25; |
> | bx:=ButterworthNLPOrder(Os,ap,as); |
Compute new value of stopband attenuation
> | Butterworth_asnew(bx); |
Compute power transfer ratio and characteristic function for Butterworth approximation
> | Butterworth(bx,s); |
Compute the secondary parameter epsilon and the poles of transfer function for the Butterworth approximation
> | ButterworthPoles(bx); |
See also:
LP2NLP, HP2NLP, BP2NLP, BP22NLP, BS2NLP