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lpc10
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hp100.c
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C/C++ Source or Header
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2000-05-18
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825b
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41 lines
/**********************************************************************
*
* HP100 Version 55
*
**********************************************************************
*
* 100 Hz High Pass Filter
*
* Jan 92 - corrected typo (1.937148 to 1.935715),
* rounded coefficients to 7 places,
* corrected and merged gain (.97466**4),
* merged numerator into first two sections.
*/
#include "lpcdefs.h"
hp100(speech)
float speech[];
{
int i;
float si, err;
static float z11=0.0, z21=0.0, z12=0.0, z22=0.0;
for( i = 0;i<LFRAME;i++) {
si = speech[i];
err = si + 1.859076*z11 - .8648249*z21;
si = err - 2.00*z11 + z21;
z21 = z11;
z11 = err;
err = si + 1.935715*z12 - .9417004*z22;
si = err - 2.00*z12 + z22;
z22 = z12;
z12 = err;
speech[i] = .902428*si;
}
}