statevar
Signal Modifiers:Standard Filters:Resonant
statevar
statevar
State-variable filter.
Description
Statevar is a new digital implementation of the analogue state-variable filter.
This filter has four simultaneous outputs: high-pass, low-pass,
band-pass and band-reject. This filter uses oversampling for sharper
resonance (default: 3 times oversampling). It includes a
resonance limiter that prevents the filter from getting unstable.
Syntax
ahp,alp,abp,abr statevar ain, kcf, kq [, iosamps, istor]
Initialization
iosamps -- number of times of oversampling used in the
filtering process. This will determine the maximum sharpness
of the filter resonance (Q). More oversampling allows higher Qs,
less oversampling will limit the resonance. The default is 3
times (iosamps=0).
istor --initial disposition of internal data space. Since
filtering incorporates a feedback loop of previous output,
the initial status of the storage space used is significant.
A zero value will clear the space; a non-zero value will allow
previous information to remain. The default value is 0.
Performance
ahp -- high-pass output signal.
alp -- low-pass output signal.
abp -- band-pass signal.
abr -- band-reject signal.
asig -- input signal.
kcf -- filter cutoff frequency
kq -- filter Q. This value is limited internally depending on
the frequency and the number of times of oversampling used in
the process (3-times oversampling by default).
Examples
Example
kenv linseg 0,0.1,1, p3-0.2,1, 0.1, 0
asig buzz 16000*kenv, 100, 100, 1;
kf expseg 100, p3/2, 5000, p3/2, 1000
ahp,alp,abp,abr statevar asig, kf, 200
outs alp,ahp
Credits
Author: Victor Lazzarini;
January 2005
New plugin in version 5
January 2005.