biquad - Biquad IIR filter
loadrt biquad
[count=N|names=name1[,name2...]]
Biquad IIR filter. Implements the following transfer function:
H(z) = (n0 + n1z-1 + n2z-2) / (1+ d1z-1 + d2z-2)
- biquad.N.in
float in
- Filter input.
- biquad.N.out
float out
- Filter output.
- biquad.N.enable
bit in (default: 0)
- Filter enable. When false, the in pin is passed to the out
pin without any filtering. A transition from false to true causes
filter coefficients to be calculated according to the current type
and the describing pin and parameter settings
- biquad.N.valid
bit out (default: 0)
- When false, indicates an error occurred when calculating filter
coefficients (require 2>Q>0.5 and
f0>sampleRate/2)
- biquad.N.type
u32 in (default: 0)
- Filter type determines the type of filter coefficients calculated. When 0,
coefficients must be loaded directly from the n0,n1,n2,d1 params.
When 1, a low pass filter is created specified by the f0,Q pins.
When 2, a notch filter is created specified by the f0,Q pins.
- biquad.N.f0
float in (default: 250.0)
- The corner frequency of the filter.
- biquad.N.Q
float in (default: 0.7071)
- The Q of the filter.
- biquad.N.s1
float out (default: 0.0)
- 1st-delayed internal state (for debug only)
- biquad.N.s2
float out (default: 0.0)
- 2nd-delayed internal state (for debug only)