syntfil[LP2NLP] - frequency transformation from the lowpass (LP) to the normalized lowpass (NLP) filter specification
Calling sequence:
LP2NLP(fp, fs, ap, as)
Parameters:
fp - cutoff frequency [Hz]
fs - stopband frequency [Hz]
ap - passband ripple [dB]
as - stopband attenuation [dB]
All parameters must be positive real values, where fp < fs and ap < as .
Description:
Os - stopband frequency of the normalized lowpass filter [1/s]
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 specification of NLP (Os, ap, as)
3 - as level 2 + print specification of the entered LP (fp, fs, ap, as) and plot the LP filter specification
4 - as level 3 + plot specification of NLP
Example:
> | with(syntfil): |
> | infolevel[syntfil]:=1; |
> | x:=LP2NLP(1000,2000,3,40); |
> | infolevel[syntfil]:=4; |
> | LP2NLP(1000,2000,3,40); |
Filter specification:
fp = 1000.000000 Hz
fs = 2000.000000 Hz
ap = 3.000000 dB
as = 40.000000 dB
Specification of NLP:
Os = 2.000000 1/s
ap = 3.000000 dB
as = 40.000000 dB