ossia::one_pole_filter< T > Struct Template Reference

First-order low-pass. The building block for everything below. More...

Detailed Description

template<typename T = float>
struct ossia::one_pole_filter< T >

First-order low-pass. The building block for everything below.

The coefficient is passed per-sample instead of being stored, so that the same filter can be driven by a varying dt or a varying cutoff without recomputing any internal state.

Public Types
using	value_type = T

Public Member Functions
OSSIA_INLINE void	reset () noexcept
	Forget the history: the next sample restarts the filter.
OSSIA_INLINE void	reset (T x) noexcept
	Restart the filter as if x had just been output.
OSSIA_INLINE void	assign_parameters (const one_pole_filter &) noexcept
	No runtime parameters: the coefficient is passed per-sample.
OSSIA_INLINE T	operator() (T x, T alpha) noexcept

Public Attributes
T	y {}
	Last output. Only meaningful once primed.
bool	primed {}

Member Function Documentation

operator()()

template<typename T = float>

OSSIA_INLINE T ossia::one_pole_filter< T >::operator() ( T  x, T  alpha  )

inlinenoexcept

Parameters

x	Input sample.
alpha	Smoothing factor in [0, 1], e.g. from lowpass_alpha().

Member Data Documentation

primed

template<typename T = float>

bool ossia::one_pole_filter< T >::primed {}

False until the first sample went through: the first sample is passed along untouched rather than being smoothed from an arbitrary zero.