cmProc5.h/c : Added cmGoldCode.

cmProc5.c

@@ -16,7 +16,11 @@
 #include "cmProcObj.h"
 #include "cmProcTemplate.h"
 #include "cmMath.h"
+#include "cmFile.h"
+#include "cmTime.h"
+#include "cmMidi.h"
 #include "cmProc.h"
+#include "cmProc2.h"
 #include "cmProc5.h"
 
 #include "cmVectOps.h"
@@ -123,3 +127,219 @@ cmRC_t cmGoertzelExec( cmGoertzel* p, const cmSample_t* inpV, unsigned procSmpCn
 }
 
 
+//=======================================================================================================================
+double _cmGoldSigSinc( double t, double T )
+{
+  double x = t/T;
+  return x == 0 ? 1.0 : sin(M_PI*x)/(M_PI*x);         
+}
+
+void _cmGoldSigRaisedCos(  cmSample_t* yV, int yN, double sPc, double beta )
+{
+  int i;
+  
+  for(i=0; i<yN; ++i)
+  {
+    double t   = i - yN/2;
+    double den = 1 - (4*(beta*beta)*(t*t) / (sPc*sPc));
+    double a;
+      
+    if(fabs(den) < 0.00001 )
+      a = 1;
+    else
+      a = cos(M_PI * beta * t/ sPc ) / den;
+
+    yV[i] = _cmGoldSigSinc(t,sPc) * a;  
+  }
+}
+
+void _cmGoldSigConv( cmGoldSig_t* p, unsigned chIdx )
+{
+  int i;
+  int sPc = p->a.samplesPerChip;
+  int osf = p->a.rcosOSFact;
+
+  // for each bit in the spreading-code
+  for(i=0; i<p->mlsN; ++i)
+  {
+    int j = (i*sPc) + sPc/2;  // index into bbV[] of center of impulse response
+    int k = j - (sPc*osf)/2;  // index into bbV[] of start of impulse response
+    int h;
+
+    // for each sample in the impulse response
+    for(h=0; h<p->rcosN; ++h,++k)
+    {
+     
+      while( k<0 )
+        k += p->sigN;
+
+      while( k>=p->sigN )
+        k -= p->sigN;
+
+      p->ch[chIdx].bbV[k] += p->ch[chIdx].pnV[i] * p->rcosV[h];     
+    }
+  }
+}
+
+void _cmGoldSigModulate( cmGoldSig_t* p, unsigned chIdx )
+{
+  unsigned    i;
+  double      rps = 2.0 * M_PI * p->a.carrierHz / p->a.srate;
+  cmSample_t* yV  = p->ch[chIdx].mdV;
+  cmSample_t* bbV = p->ch[chIdx].bbV;
+
+  for(i=0; i<p->sigN; ++i)
+    yV[ i ] = bbV[i]*cos(rps*i) + bbV[i]*sin(rps*i);
+
+  // apply a half Hann envelope to the onset/offset of the id signal
+  if( p->a.envMs > 0 )
+  {
+    unsigned   wndMs = p->a.envMs * 2;
+    unsigned   wndN  = wndMs * p->a.srate / 1000;
+    wndN += wndN % 2 ? 0 : 1;   // force the window length to be odd
+    unsigned   wNo2 = wndN/2 + 1;
+    cmSample_t wndV[ wndN ];
+    cmVOS_Hann(wndV,wndN);
+    cmVOS_MultVV(yV,wNo2,wndV);
+    cmVOS_MultVV(yV + p->sigN - wNo2, wNo2, wndV + wNo2 - 1);
+  }
+
+}
+
+cmGoldSig_t* cmGoldSigAlloc( cmCtx* ctx, cmGoldSig_t* p, const cmGoldSigArg_t* a )
+{
+  cmGoldSig_t* op = cmObjAlloc(cmGoldSig_t,ctx,p);
+  
+  if( a != NULL )  
+    if( cmGoldSigInit(op,a) != cmOkRC )
+      cmGoldSigFree(&op);
+
+  return op;
+
+}
+
+cmRC_t cmGoldSigFree( cmGoldSig_t** pp )
+{
+  cmRC_t rc = cmOkRC;
+
+  if( pp == NULL || *pp == NULL )
+    return rc;
+
+  cmGoldSig_t* p = *pp;
+
+  if((rc = cmGoldSigFinal(p)) != cmOkRC )
+    return rc;
+  
+  unsigned i;
+  for(i=0; i<p->a.chN; ++i)
+  {
+    cmMemFree(p->ch[i].bbV);
+    cmMemFree(p->ch[i].mdV);
+  }
+  
+  cmMemFree(p->ch);
+  cmMemFree(p->rcosV);
+  cmMemFree(p->pnM);
+  cmMemFree(p);
+  *pp = NULL;
+
+  return rc;
+}
+
+cmRC_t cmGoldSigInit( cmGoldSig_t* p, const cmGoldSigArg_t* a )
+{
+  cmRC_t      rc = cmOkRC;
+  unsigned    i;
+  
+  p->a      = *a;                                            // store arg recd
+  p->ch     = cmMemResizeZ(cmGoldSigCh_t,p->ch,a->chN);  // alloc channel array
+  p->mlsN   = (1 << a->lfsrN) - 1;                           // calc spreading code length
+  p->rcosN  = a->samplesPerChip * a->rcosOSFact;             // calc rcos imp. resp. length
+  p->rcosN += (p->rcosN % 2)==0;                             // force rcos imp. length odd               
+  p->rcosV  = cmMemResizeZ(cmSample_t,p->rcosV,p->rcosN);  // alloc rcos imp. resp. vector
+  p->pnM    = cmMemResizeZ(int,p->pnM,p->mlsN*a->chN);   // alloc spreading-code mtx
+  p->sigN   = p->mlsN * a->samplesPerChip;                   // calc audio signal length
+
+  // generate spreading codes
+  if( cmGenGoldCodes(a->lfsrN, a->mlsCoeff0, a->mlsCoeff1, a->chN, p->pnM, p->mlsN ) == false )
+  {
+    rc = cmCtxRtCondition(&p->obj,cmSubSysFailRC,"Unable to generate sufficient balanced Gold codes.");
+    goto errLabel;
+  }
+
+  // generate the rcos impulse response
+  _cmGoldSigRaisedCos(p->rcosV,p->rcosN,a->samplesPerChip,a->rcosBeta);
+
+  // for each channel
+  for(i=0; i<a->chN; ++i)
+  {
+    // Note: if (i*p->mlsN) is set to 0 in the following line then all channels
+    // will use the same spreading code.
+    p->ch[i].pnV = p->pnM + (i*p->mlsN);                        // get ch. spreading code
+    p->ch[i].bbV = cmMemResizeZ(cmSample_t,p->ch[i].bbV,p->sigN); // alloc baseband signal vector
+    p->ch[i].mdV = cmMemResizeZ(cmSample_t,p->ch[i].mdV,p->sigN); // alloc output audio vector
+
+    // Convolve spreading code with rcos impulse reponse to form baseband signal.
+    _cmGoldSigConv(p, i );     
+
+    // Modulate baseband signal to carrier frq. and apply attack/decay envelope.
+    _cmGoldSigModulate(p, i );
+  }
+
+ errLabel:
+  if((rc = cmErrLastRC(&p->obj.err)) != cmOkRC )
+    cmGoldSigFree(&p);
+
+  return rc;
+}
+
+cmRC_t cmGoldSigFinal( cmGoldSig_t* p )
+{ return cmOkRC; }
+
+cmRC_t cmGoldSigWrite( cmCtx* ctx, cmGoldSig_t* p, const char* fn )
+{
+  cmVectArray_t* vap = NULL;
+  unsigned       i;
+
+  vap = cmVectArrayAlloc(ctx,kSampleVaFl);
+
+  for(i=0; i<p->a.chN; ++i)
+  {
+    cmVectArrayAppendS(vap,p->ch[i].bbV,p->sigN);
+    cmVectArrayAppendS(vap,p->ch[i].mdV,p->sigN);
+  }
+
+  cmVectArrayWrite(vap,fn);
+
+  cmVectArrayFree(&vap);
+
+  return cmOkRC;
+}
+
+
+cmRC_t cmGoldSigGen( cmGoldSig_t* p, unsigned chIdx, unsigned prefixN, unsigned dsN, unsigned *bsiV, unsigned bsiN, double noiseGain, cmSample_t** yVRef, unsigned* yNRef )
+{
+  unsigned    yN = prefixN + bsiN * (p->sigN + dsN);
+  cmSample_t* yV = cmMemAllocZ(cmSample_t,yN);
+  unsigned    i;
+
+  cmVOS_Random(yV, yN, -noiseGain, noiseGain );
+
+  for(i=0; i<bsiN; ++i)
+  {
+    bsiV[i] = prefixN + i*(p->sigN + dsN);
+    
+    cmVOS_AddVV(yV + bsiV[i], p->sigN, p->ch[chIdx].mdV );
+  }
+  
+  if( yVRef != NULL )
+    *yVRef = yV;
+
+  if( yNRef != NULL )
+    *yNRef = yN;
+
+  return cmOkRC;  
+}
+
+
+

cmProc5.h

@@ -39,7 +39,76 @@ extern "C" {
   cmRC_t cmGoertzelExec( cmGoertzel* p, const cmSample_t* in, unsigned procSmpCnt,  double* outV, unsigned chCnt );
 
 
+  //=======================================================================================================================
+  // Gold Code Signal Generator
+  //
+
+  typedef struct
+  {
+    unsigned chN;              // count of channels (each channel has a unique id)   
+    double   srate;            // system sample rate (samples/second)
+    unsigned lfsrN;            // linear feedback shift register (LFSR) length used to form Gold codes
+    unsigned mlsCoeff0;        // LFSR coeff. 0
+    unsigned mlsCoeff1;        // LFSR coeff. 1
+    unsigned samplesPerChip;   // samples per spreading code bit
+    double   rcosBeta;         // raised cosine impulse response beta coeff.
+    unsigned rcosOSFact;       // raised cosine impulse response oversample factor
+    double   carrierHz;        // carrier frequency
+    double   envMs;            // attack/decay envelope duration
+  } cmGoldSigArg_t;
+
+  typedef struct
+  {
+    int*        pnV;  // pnV[ mlsN ]  spread code (aliased from pnM[:,i])
+    cmSample_t* bbV;  // bbV[ sigN ]  baseband signal  at audio rate
+    cmSample_t* mdV;  // mdV[ sigN ]  modulated signal at audio rate
+  } cmGoldSigCh_t;
+
+  typedef struct 
+  {
+    cmObj          obj;         // 
+    cmGoldSigArg_t a;           // argument record
+    cmGoldSigCh_t* ch;          // ch[ chN ] channel array
+    int*           pnM;         // pnM[mlsN,chN] (aliased to ch[].pnV)
+    cmSample_t*    rcosV;       // rcosV[rcosN] raised cosine impulse response
+    unsigned       rcosN;       // length of raised cosine impulse response
+    unsigned       mlsN;        // length of Gold codes (Maximum length sequence length)
+    unsigned       sigN;        // length of channel signals bbV[] and mdV[]  
+  } cmGoldSig_t;
+
+
+  cmGoldSig_t* cmGoldSigAlloc( cmCtx* ctx, cmGoldSig_t* p, const cmGoldSigArg_t* a );
+  cmRC_t cmGoldSigFree( cmGoldSig_t** pp );
+
+  cmRC_t cmGoldSigInit( cmGoldSig_t* p, const cmGoldSigArg_t* a );
+  cmRC_t cmGoldSigFinal( cmGoldSig_t* p );
+  
+  cmRC_t cmGoldSigWrite( cmCtx* ctx, cmGoldSig_t* p, const char* fn );
+
+  // Generate a signal consisting of  underlying white noise with 
+  // bsiN repeated copies of the id signal associated with 
+  // channel 'chIdx'. Each discrete id signal copy is separated by 'dsN' samples.
+  // The signal will be prefixed with 'prefixN' samples of silence (noise).
+  // On return sets 'yVRef' to point to the generated signal and 'yNRef'
+  // to the count of samples in 'yVRef'.
+  // On error sets yVRef to NULL and  yNRef to zero.
+  // The vector returned in 'yVRef' should be freed via atMemFree().
+  // On return sets bsiV[bsiN] to the onset sample index of each id signal copy.
+  // The background noise signal is limited to the range -noiseGain to noiseGain.
+  cmRC_t cmGoldSigGen( 
+    cmGoldSig_t*   p, 
+    unsigned      chIdx, 
+    unsigned      prefixN, 
+    unsigned      dsN, 
+    unsigned     *bsiV, 
+    unsigned      bsiN, 
+    double        noiseGain, 
+    cmSample_t**  yVRef, 
+    unsigned*     yNRef );
+
+  cmRC_t cmGoldSigTest( cmCtx* ctx );
 
+  
 #ifdef __cplusplus
 }
 #endif