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FormSwep Class Reference

#include <FormSwep.h>

Inheritance diagram for FormSwep:

BiQuad Filter Stk List of all members.

Detailed Description

STK sweepable formant filter class.

This public BiQuad filter subclass implements a formant (resonance) which can be "swept" over time from one frequency setting to another. It provides methods for controlling the sweep rate and target frequency.

by Perry R. Cook and Gary P. Scavone, 1995 - 2007.


Public Member Functions

 FormSwep ()
 Default constructor creates a second-order pass-through filter.
 ~FormSwep ()
 Class destructor.
void setResonance (StkFloat frequency, StkFloat radius)
 Sets the filter coefficients for a resonance at frequency (in Hz).
void setStates (StkFloat frequency, StkFloat radius, StkFloat gain=1.0)
 Set both the current and target resonance parameters.
void setTargets (StkFloat frequency, StkFloat radius, StkFloat gain=1.0)
 Set target resonance parameters.
void setSweepRate (StkFloat rate)
 Set the sweep rate (between 0.0 - 1.0).
void setSweepTime (StkFloat time)
 Set the sweep rate in terms of a time value in seconds.


Member Function Documentation

void FormSwep::setResonance StkFloat  frequency,
StkFloat  radius
 

Sets the filter coefficients for a resonance at frequency (in Hz).

This method determines the filter coefficients corresponding to two complex-conjugate poles with the given frequency (in Hz) and radius from the z-plane origin. The filter zeros are placed at z = 1, z = -1, and the coefficients are then normalized to produce a constant unity gain (independent of the filter gain parameter). The resulting filter frequency response has a resonance at the given frequency. The closer the poles are to the unit-circle (radius close to one), the narrower the resulting resonance width.

void FormSwep::setSweepRate StkFloat  rate  ) 
 

Set the sweep rate (between 0.0 - 1.0).

The formant parameters are varied in increments of the sweep rate between their current and target values. A sweep rate of 1.0 will produce an immediate change in resonance parameters from their current values to the target values. A sweep rate of 0.0 will produce no change in resonance parameters.

void FormSwep::setSweepTime StkFloat  time  ) 
 

Set the sweep rate in terms of a time value in seconds.

This method adjusts the sweep rate based on a given time for the formant parameters to reach their target values.


The documentation for this class was generated from the following file:
The Synthesis ToolKit in C++ (STK)
©1995-2007 Perry R. Cook and Gary P. Scavone. All Rights Reserved.