jass.generators
Class RightLoadedWebsterTube

java.lang.Object
  jass.generators.RightLoadedWebsterTube

All Implemented Interfaces:

Filter, TwoMassModel.PressureServer

public class RightLoadedWebsterTube
extends java.lang.Object
implements Filter, TwoMassModel.PressureServer

Author:

Kees van den Doel (kvdoel@cs.ubc.ca) Implement Webster equation with open left end where velocity is prescribed (glottal source) and right side terminated in baffle in infinite plane. Physical quantities (capitals) are P (pressure) RHO (density) PHO0 (equilibrium density) U velocity, F force/volume on fluid, S area of tube. c is sound speed. L length of tube [0 L]. Dimensionless quantities u,p, and f of dimension 1/m^2 are introduced: RHO=RHO0*(1+p) U = c*u f = F/(c*RHO0) To translate between these and Peter Birkholz's varaibles (Interspeech 04 and thesis): (S = area, C = circumferencem, h = segment length). Peter Kees u/(cS) u p/(rho c^2) p 2*S*R_i/(h*rho) d(S) u_w h*C*z u_{N+1} cS(L)v u_{N+2} cS(L)w Continuum eq. are: du/dt + c*dp/dx + (dWall*c/sqrt(S))*u - (dSecond*c/sqrt(S))* d^2u/dx^2 = f(x,t) [1a] d(Sp)/dt + c*d(Su)/dx = - C(x)*z [1b] M dz/dt + Bz + Ky = p [1c] dy/dt = z [1d] u(0) = ug (given source: glottal velocity) [1e] u(L) = v. [1f] where C(x) is the circumference. In the paper AscherDoel07 we call (dWall*c/sqrt(S))=d(S). v satisfies eq. for radiation impedance: v = dw/dt*L_R/R_R + w, [2a] dw/dt = rho*c/(L_R*S_end) * p(L) [2b] ( Birkholz has this in the form where on LHS of [2b] there are extra terms h*rho/(2*L_R*S) dv/dt + h*rho*d(S)/(2*L_R*S) v ) where (c.f. Birkholz Interspeech 04) L_R = 8 rho/(3pi sqrt(pi S_end) R_R = 128rho c/(9 pi^2 S_end). M = Mw/(rhoc^2) B = Bw/(rhoc^2) K = Kw/(rhoc^2) with Mw=21, Bw=8000, Kw=845000 (see Birkholz 04). In the code w is called u_N2 and v is pu[N-1] (i.e., last element in array). dWall is an attenuation factor, as is dSecond. Discretization with staggered grid, u on even points, p on odd, S on both. Grid of N points x = i*h, N odd, grid space h. The wall vibration parameters z,y live on the same nodes as pressure. CFL condition is: eta = c*dt/2h < 1. Or h = c*dt/(2*eta). We would expect the cutoff freq. to be (eta/2)*Fs with Fs sampling rate. In practice the cutoff is lower, about (eta/2.5) * Fs. (Why?) We determine N from the minimum L we want to simulate, then increase h when appropriate for longer tubes. To get freq. up to (roughly) srate/2 resolved we have to oversample with a factor 2. Grid state vector x(i) i = 0,...,N-1: (NB N is odd) x(i) = u(i*h) i=0,2,...,N-1 x(i) = p(i*h) i=1,3,...,N-2 0 1 2 3 4 5 6 (N=7,NNasal=5) u p u p u p u uN[0] pN[1] uN[2] pN[3] uN[4] Discretize Eq. 1a-e using symplectic Euler, i.e., update u first, then update p in terms of the new u's. Note that the last u is really the u outside the lips so the actual length of the tract is up to the last pressure. Nasal tract id coupled at a pressure pivot point, so the nasal tract has an odd number NNasal of grid points starting with a velocity point coupled to the pivot pressure. So if the area SNasal[0] (leftmost) is zero the nasal tract decouples. Theoretically we need a damping dW(om) * c/sqrt(S) with freq. dependent dW given by (see Birkholz 04) dW(om)=sqrt[pi * mu*om/(rho c^2)]. We can approximate by dWall*c/sqrt(S) * u - dSecond*c/sqrt(S) * u_xx and chose dWall and dSecond to match as closely as possible. So make them equal at om1 and om2. This results in dSecond = [dW(om2)-dW(om1)]/[(om2/c)^2-(om1/c)^2] dWall = dW(om1) - dSecond*(om1/c)^2

Field Summary

protected double[]	aa
protected double[]	bb
protected double	BWall
protected double	c
protected double[]	cc
protected double	CFLNumber
double	d
protected double[]	dd
double	dSecond
protected double	dt
double	dWall
double	dWallNasal
protected double	eta
protected double	etaNasal
protected double	flowNoiseBandwidth
protected double	flowNoiseFrequency
protected double	flowNoiseLevel
protected double	h
protected double	hMin
protected double	hMinNasal
protected double	hNasal
protected int	iNasal
protected double	KWall
protected double	len
protected double	lenNasal
double	lipAreaMultiplier
double	M
protected double	minLen
protected double	minLenNasal
double	mouthNoseBalance
double	multD
double	multDSecond
double	multDWall
double	multM
protected double	muVisc
protected double	MWall
protected int	N
protected int	nn
protected int	NNasal
protected int	nnNasal
double	om1
double	om2
protected double[]	outBuf
protected int	overSamplingFactor
protected double[]	pu
protected double[]	pu_noise
protected double[]	pu_old
protected double[]	puNasal
protected double	relativeLocationOfNasalTract
protected double[]	S
protected double[]	SNasal
protected double[]	Snow
protected double[]	SnowNasal
protected double[]	Sold
protected double[]	SoldNasal
protected double[]	Sprev
protected double[]	SprevNasal
protected double[]	sqrtS
protected double[]	sqrtSNasal
protected double[]	sqrtSold
protected double[]	sqrtSoldNasal
protected float	srate Sampling rate in Hertz.
protected TubeShape	tubeShape
protected TubeShape	tubeShapeNasal
protected boolean	twoMassCouplingOn
protected TwoMassModel	twoMassModel
protected double	u_N2
protected double	u_N2_nose
boolean	useLipModel
double	velumNasal
protected double	wallPressureCoupling
protected double[]	yWall
protected double[]	yWallNasal
protected double[]	zWall
protected double[]	zWallNasal

Constructor Summary

RightLoadedWebsterTube(float srate, TubeShape tm, double minLen)

RightLoadedWebsterTube(float srate, TubeShape tm, double minLen, TubeShape tmNasal, double minLenNasal)

RightLoadedWebsterTube(float srate, TubeShape tm, double minLen, TubeShape tmNasal, double minLenNasal, double cflNumber)

Method Summary

void	allocate()
void	changeTubeModel()
protected void	computeDampingPars()
void	filter(float[] output, float[] input, int nsamples, int inputOffset) Proces input (may be same as output).
void	filterIMEX(float[] output, float[] input, int nsamples, int inputOffset) Uses IMEX Euler as in paper with Uri Ascher
double	getA1() Implement TwoMassModel.PressureServer
double	getCFLNumber()
double	getFlowNoiseBandwidth()
double	getFlowNoiseFrequency()
double	getFlowNoiseLevel()
boolean	getOutputVelocity()
double	getPressure() Implement TwoMassModel.PressureServer
TwoMassModel	getTwoMassModel()
double	getWallPressureCoupling()
void	reset()
void	setCFLNumber(double val)
void	setFlowNoiseBandwidth(double v)
void	setFlowNoiseFrequency(double v)
void	setFlowNoiseLevel(double v)
void	setOm1(double val)
void	setOm2(double val)
void	setOutputVelocity(boolean val)
void	setTwoMassModel(TwoMassModel twoMassModel)
void	setWallPressureCoupling(double val)
protected void	updateFlowFilter()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

srate

protected float srate

Sampling rate in Hertz.

minLen

protected double minLen

minLenNasal

protected double minLenNasal

c

protected double c

wallPressureCoupling

protected double wallPressureCoupling

MWall

protected double MWall

BWall

protected double BWall

KWall

protected double KWall

muVisc

protected double muVisc

om1

public double om1

om2

public double om2

len

protected double len

lenNasal

protected double lenNasal

velumNasal

public double velumNasal

h

protected double h

hMin

protected double hMin

hNasal

protected double hNasal

hMinNasal

protected double hMinNasal

N

protected int N

NNasal

protected int NNasal

M

public double M

d

public double d

lipAreaMultiplier

public double lipAreaMultiplier

multM

public double multM

multD

public double multD

dWall

public double dWall

multDSecond

public double multDSecond

multDWall

public double multDWall

dSecond

public double dSecond

S

protected double[] S

Sold

protected double[] Sold

Snow

protected double[] Snow

Sprev

protected double[] Sprev

sqrtS

protected double[] sqrtS

sqrtSold

protected double[] sqrtSold

pu

protected double[] pu

yWall

protected double[] yWall

zWall

protected double[] zWall

u_N2

protected double u_N2

u_N2_nose

protected double u_N2_nose

pu_old

protected double[] pu_old

pu_noise

protected double[] pu_noise

aa

protected double[] aa

bb

protected double[] bb

cc

protected double[] cc

dd

protected double[] dd

nn

protected int nn

nnNasal

protected int nnNasal

tubeShape

protected TubeShape tubeShape

dWallNasal

public double dWallNasal

SNasal

protected double[] SNasal

SoldNasal

protected double[] SoldNasal

SnowNasal

protected double[] SnowNasal

SprevNasal

protected double[] SprevNasal

sqrtSNasal

protected double[] sqrtSNasal

sqrtSoldNasal

protected double[] sqrtSoldNasal

puNasal

protected double[] puNasal

yWallNasal

protected double[] yWallNasal

zWallNasal

protected double[] zWallNasal

tubeShapeNasal

protected TubeShape tubeShapeNasal

outBuf

protected double[] outBuf

relativeLocationOfNasalTract

protected double relativeLocationOfNasalTract

iNasal

protected int iNasal

overSamplingFactor

protected int overSamplingFactor

useLipModel

public boolean useLipModel

dt

protected double dt

eta

protected double eta

etaNasal

protected double etaNasal

mouthNoseBalance

public double mouthNoseBalance

twoMassModel

protected TwoMassModel twoMassModel

twoMassCouplingOn

protected boolean twoMassCouplingOn

CFLNumber

protected double CFLNumber

flowNoiseLevel

protected double flowNoiseLevel

flowNoiseBandwidth

protected double flowNoiseBandwidth

flowNoiseFrequency

protected double flowNoiseFrequency

Constructor Detail

RightLoadedWebsterTube

public RightLoadedWebsterTube(float srate,
                              TubeShape tm,
                              double minLen)

RightLoadedWebsterTube

public RightLoadedWebsterTube(float srate,
                              TubeShape tm,
                              double minLen,
                              TubeShape tmNasal,
                              double minLenNasal)

RightLoadedWebsterTube

public RightLoadedWebsterTube(float srate,
                              TubeShape tm,
                              double minLen,
                              TubeShape tmNasal,
                              double minLenNasal,
                              double cflNumber)

Method Detail

setCFLNumber

public void setCFLNumber(double val)

getCFLNumber

public double getCFLNumber()

setOutputVelocity

public void setOutputVelocity(boolean val)

setOm1

public void setOm1(double val)

setOm2

public void setOm2(double val)

setWallPressureCoupling

public void setWallPressureCoupling(double val)

getWallPressureCoupling

public double getWallPressureCoupling()

computeDampingPars

protected void computeDampingPars()

getOutputVelocity

public boolean getOutputVelocity()

allocate

public void allocate()

getTwoMassModel

public TwoMassModel getTwoMassModel()

setTwoMassModel

public void setTwoMassModel(TwoMassModel twoMassModel)

changeTubeModel

public void changeTubeModel()

reset

public void reset()

setFlowNoiseLevel

public void setFlowNoiseLevel(double v)

getFlowNoiseLevel

public double getFlowNoiseLevel()

setFlowNoiseFrequency

public void setFlowNoiseFrequency(double v)

getFlowNoiseFrequency

public double getFlowNoiseFrequency()

setFlowNoiseBandwidth

public void setFlowNoiseBandwidth(double v)

getFlowNoiseBandwidth

public double getFlowNoiseBandwidth()

updateFlowFilter

protected void updateFlowFilter()

getPressure

public double getPressure()

Implement TwoMassModel.PressureServer

Specified by:

getPressure in interface TwoMassModel.PressureServer

getA1

public double getA1()

Implement TwoMassModel.PressureServer

Specified by:

getA1 in interface TwoMassModel.PressureServer

filter

public void filter(float[] output,
                   float[] input,
                   int nsamples,
                   int inputOffset)

Proces input (may be same as output). Implements Filter interface

Specified by:

filter in interface Filter

Parameters:

output - user provided buffer for returned result.

input - user provided input buffer.

nsamples - number of samples written to output buffer.

inputOffset - where to start in circular buffer input (unused)

filterIMEX

public void filterIMEX(float[] output,
                       float[] input,
                       int nsamples,
                       int inputOffset)

Uses IMEX Euler as in paper with Uri Ascher