mirror of
https://github.com/thestk/stk
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65 lines
1.6 KiB
C++
65 lines
1.6 KiB
C++
/*******************************************/
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/* One Zero Filter Class, */
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/* by Perry R. Cook, 1995-96 */
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/* The parameter gain is an additional */
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/* gain parameter applied to the filter */
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/* on top of the normalization that takes */
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/* place automatically. So the net max */
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/* gain through the system equals the */
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/* value of gain. sgain is the combina- */
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/* tion of gain and the normalization */
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/* parameter, so if you set the poleCoeff */
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/* to alpha, sgain is always set to */
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/* gain / (1.0 - fabs(alpha)). */
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/*******************************************/
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#include "OneZero.h"
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OneZero :: OneZero()
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{
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gain = (MY_FLOAT) 1.0;
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zeroCoeff = (MY_FLOAT) 1.0;
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sgain = (MY_FLOAT) 0.5;
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inputs = (MY_FLOAT *) malloc(sizeof(MY_FLOAT));
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this->clear();
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}
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OneZero :: ~OneZero()
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{
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free(inputs);
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}
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void OneZero :: clear()
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{
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inputs[0] = (MY_FLOAT) 0.0;
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lastOutput = (MY_FLOAT) 0.0;
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}
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void OneZero :: setGain(MY_FLOAT aValue)
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{
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gain = aValue;
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if (zeroCoeff > 0.0) // Normalize gain to 1.0 max
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sgain = gain / ((MY_FLOAT) 1.0 + zeroCoeff);
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else
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sgain = gain / ((MY_FLOAT) 1.0 - zeroCoeff);
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}
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void OneZero :: setCoeff(MY_FLOAT aValue)
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{
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zeroCoeff = aValue;
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if (zeroCoeff > 0.0) // Normalize gain to 1.0 max
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sgain = gain / ((MY_FLOAT) 1.0 + zeroCoeff);
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else
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sgain = gain / ((MY_FLOAT) 1.0 - zeroCoeff);
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}
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MY_FLOAT OneZero :: tick(MY_FLOAT sample) // Perform Filter Operation
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{
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MY_FLOAT temp;
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temp = sgain * sample;
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lastOutput = (inputs[0] * zeroCoeff) + temp;
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inputs[0] = temp;
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return lastOutput;
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}
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