www.pudn.com > lib.zip > tonedec.C

#include  
 
#include "private.h" 
#include "complex.h" 
#include "filters.h" 
#include "tonedec.h" 
 
#define THRESH 0.1	/* tone threshold */ 
 
inline float fsgn(float x) { return (x > 0.0f) ? +1.0f : (x < 0.0f) ? -1.0f : 0.0f; } 
inline float sqr(float f)  { return f*f;					    } 
 
 
tone_detector::tone_detector(fspec *fefs, fspec *bpfs, fspec *lpfs, bool lim) 
  { fef = new filter(fefs); 
    bpf = new filter(bpfs); 
    lpf = new filter(lpfs); 
    limit = lim; 
    pow = 0.0; prescount = 0; present = false; 
  } 
 
tone_detector::~tone_detector() 
  { delete fef; delete bpf; delete lpf; 
  } 
 
void tone_detector::insert(float x) 
  { x = fef -> fstep(x);	    /* front-end filter to remove d.c. */ 
    if (limit) x = fsgn(x);	    /* hard limit */ 
    float y = bpf -> fstep(x); 
    pow = lpf -> fstep(sqr(y)); 
    present = (pow >= THRESH); 
    if (present) prescount++; else prescount = 0; 
  } 
 
void tone_detector::debug() 
  { fprintf(stderr, "    %14.5e (%5d)", pow, prescount); 
  }