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60 lines
1.6 KiB
C++
60 lines
1.6 KiB
C++
/***************************************************/
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/*! \class ReedTable
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\brief STK reed table class.
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This class implements a simple one breakpoint,
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non-linear reed function, as described by
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Smith (1986). This function is based on a
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memoryless non-linear spring model of the reed
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(the reed mass is ignored) which saturates when
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the reed collides with the mouthpiece facing.
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See McIntyre, Schumacher, & Woodhouse (1983),
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Smith (1986), Hirschman, Cook, Scavone, and
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others for more information.
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by Perry R. Cook and Gary P. Scavone, 1995 - 2005.
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*/
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/***************************************************/
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#include "ReedTable.h"
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using namespace Nyq;
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ReedTable :: ReedTable()
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{
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offset_ = (StkFloat) 0.6; // Offset is a bias, related to reed rest position.
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slope_ = (StkFloat) -0.8; // Slope corresponds loosely to reed stiffness.
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}
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ReedTable :: ~ReedTable()
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{
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}
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void ReedTable :: setOffset(StkFloat offset)
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{
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offset_ = offset;
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}
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void ReedTable :: setSlope(StkFloat slope)
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{
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slope_ = slope;
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}
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StkFloat ReedTable :: computeSample(StkFloat input)
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{
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// The input is differential pressure across the reed.
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lastOutput_ = offset_ + (slope_ * input);
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// If output is > 1, the reed has slammed shut and the
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// reflection function value saturates at 1.0.
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if (lastOutput_ > 1.0) lastOutput_ = (StkFloat) 1.0;
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// This is nearly impossible in a physical system, but
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// a reflection function value of -1.0 corresponds to
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// an open end (and no discontinuity in bore profile).
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if (lastOutput_ < -1.0) lastOutput_ = (StkFloat) -1.0;
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return lastOutput_;
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}
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