Struct synfx_dsp::fh_va::LadderFilter

pub struct LadderFilter {
    pub params: Arc<FilterParams>,
    pub s: [f32x4; 4],
    /* private fields */
}

This is a 4-pole lowpass ladder filter.

This is a 4-pole lowpass ladder filter loosely based on the ones found in Moog synthesizers. It distorts nicely and is capable of stable self-oscillation when k_ladder==4, and can output other slopes too.

Resonance is limited by the differential BJT buffers.

It converges very well, usually only taking 2 iterations, and almost never more than 4. Could just always do 2, especially when oversampled.

Circuit solved by applying KCL, finding the jacobian of the entire system and then applying newton’s method.

By mixing the output of the different stages, and the output of the feedback, we can create many other filter types. See LadderMode

Fields

params: Arc<FilterParams>

s: [f32x4; 4]

Implementations

impl LadderFilter

pub fn new(params: Arc<FilterParams>) -> Self

pub fn reset(&mut self)

pub fn set_mix(&mut self, mode: LadderMode)

pub fn tick_newton(&mut self, input: f32x4) -> f32x4

performs a complete filter process (newton-raphson method)

pub fn tick_pivotal(&mut self, input: f32x4) -> f32x4

performs a complete filter process (solved with Mystran’s fixed-pivot method).

pub fn tick_linear(&mut self, input: f32x4) -> f32x4

performs a complete filter process (linear without distortion)

Trait Implementations

impl Clone for LadderFilter

fn clone(&self) -> LadderFilter

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LadderFilter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.