syntfil[BP22NLP] - frequency transformation from the symmetrical bandpass (BP) to the normalized lowpass (NLP) filter specification
Calling sequence:
BP22NLP(fm, delta_fp, delta_fs, ap, as)
Parameters:
fm - passband geometric cetre [Hz]
delta_fp - passband width [Hz]
delta_fs - stopband width [Hz]
ap - passband ripple [dB]
as - stopband attenuation [dB]
All parameters must be positive real values, where delta_fp < delta_fs a ap < as .
Description:
Os - stopband frequency of 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 values f_s, f_p, fp, fs and specification of NLP (Os, ap, as)
3 - as level 2 + print specification of entered BP (fm, delta_fp, delta_fs, ap, as) and plot BP filter specification
4 - as level 3 + plot specification of NLP
Example:
> | with(syntfil): |
> | infolevel[syntfil]:=1; |
> | x:=BP22NLP(1000,500,1000,3,40); |
> | infolevel[syntfil]:=4; |
> | BP22NLP(1000,500,1000,3,40); |
Filter specification:
fm = 1000.000000 Hz
delta_fp = 500.000000 Hz
delta_fs = 1000.000000 Hz
ap = 3.000000 dB
as = 40.000000 dB
f_s = 618.033988 Hz
f_p = 780.776406 Hz
fp = 1280.776406 Hz
fs = 1618.033988 Hz
Specification of NLP:
Os = 2.000000 1/s
ap = 3.000000 dB
as = 40.000000 dB