cmProc5.h/c : Added cmGoldCode.
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kevin
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032d359a90
commit
b1ff1dfb07
220
cmProc5.c
220
cmProc5.c
@ -16,7 +16,11 @@
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#include "cmProcObj.h"
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#include "cmProcTemplate.h"
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#include "cmMath.h"
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#include "cmFile.h"
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#include "cmTime.h"
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#include "cmMidi.h"
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#include "cmProc.h"
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#include "cmProc2.h"
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#include "cmProc5.h"
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#include "cmVectOps.h"
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@ -123,3 +127,219 @@ cmRC_t cmGoertzelExec( cmGoertzel* p, const cmSample_t* inpV, unsigned procSmpCn
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}
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//=======================================================================================================================
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double _cmGoldSigSinc( double t, double T )
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{
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double x = t/T;
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return x == 0 ? 1.0 : sin(M_PI*x)/(M_PI*x);
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}
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void _cmGoldSigRaisedCos( cmSample_t* yV, int yN, double sPc, double beta )
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{
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int i;
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for(i=0; i<yN; ++i)
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{
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double t = i - yN/2;
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double den = 1 - (4*(beta*beta)*(t*t) / (sPc*sPc));
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double a;
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if(fabs(den) < 0.00001 )
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a = 1;
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else
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a = cos(M_PI * beta * t/ sPc ) / den;
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yV[i] = _cmGoldSigSinc(t,sPc) * a;
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}
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}
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void _cmGoldSigConv( cmGoldSig_t* p, unsigned chIdx )
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{
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int i;
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int sPc = p->a.samplesPerChip;
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int osf = p->a.rcosOSFact;
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// for each bit in the spreading-code
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for(i=0; i<p->mlsN; ++i)
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{
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int j = (i*sPc) + sPc/2; // index into bbV[] of center of impulse response
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int k = j - (sPc*osf)/2; // index into bbV[] of start of impulse response
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int h;
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// for each sample in the impulse response
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for(h=0; h<p->rcosN; ++h,++k)
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{
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while( k<0 )
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k += p->sigN;
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while( k>=p->sigN )
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k -= p->sigN;
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p->ch[chIdx].bbV[k] += p->ch[chIdx].pnV[i] * p->rcosV[h];
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}
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}
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}
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void _cmGoldSigModulate( cmGoldSig_t* p, unsigned chIdx )
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{
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unsigned i;
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double rps = 2.0 * M_PI * p->a.carrierHz / p->a.srate;
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cmSample_t* yV = p->ch[chIdx].mdV;
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cmSample_t* bbV = p->ch[chIdx].bbV;
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for(i=0; i<p->sigN; ++i)
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yV[ i ] = bbV[i]*cos(rps*i) + bbV[i]*sin(rps*i);
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// apply a half Hann envelope to the onset/offset of the id signal
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if( p->a.envMs > 0 )
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{
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unsigned wndMs = p->a.envMs * 2;
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unsigned wndN = wndMs * p->a.srate / 1000;
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wndN += wndN % 2 ? 0 : 1; // force the window length to be odd
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unsigned wNo2 = wndN/2 + 1;
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cmSample_t wndV[ wndN ];
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cmVOS_Hann(wndV,wndN);
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cmVOS_MultVV(yV,wNo2,wndV);
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cmVOS_MultVV(yV + p->sigN - wNo2, wNo2, wndV + wNo2 - 1);
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}
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}
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cmGoldSig_t* cmGoldSigAlloc( cmCtx* ctx, cmGoldSig_t* p, const cmGoldSigArg_t* a )
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{
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cmGoldSig_t* op = cmObjAlloc(cmGoldSig_t,ctx,p);
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if( a != NULL )
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if( cmGoldSigInit(op,a) != cmOkRC )
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cmGoldSigFree(&op);
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return op;
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}
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cmRC_t cmGoldSigFree( cmGoldSig_t** pp )
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{
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cmRC_t rc = cmOkRC;
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if( pp == NULL || *pp == NULL )
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return rc;
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cmGoldSig_t* p = *pp;
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if((rc = cmGoldSigFinal(p)) != cmOkRC )
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return rc;
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unsigned i;
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for(i=0; i<p->a.chN; ++i)
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{
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cmMemFree(p->ch[i].bbV);
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cmMemFree(p->ch[i].mdV);
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}
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cmMemFree(p->ch);
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cmMemFree(p->rcosV);
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cmMemFree(p->pnM);
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cmMemFree(p);
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*pp = NULL;
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return rc;
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}
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cmRC_t cmGoldSigInit( cmGoldSig_t* p, const cmGoldSigArg_t* a )
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{
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cmRC_t rc = cmOkRC;
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unsigned i;
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p->a = *a; // store arg recd
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p->ch = cmMemResizeZ(cmGoldSigCh_t,p->ch,a->chN); // alloc channel array
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p->mlsN = (1 << a->lfsrN) - 1; // calc spreading code length
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p->rcosN = a->samplesPerChip * a->rcosOSFact; // calc rcos imp. resp. length
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p->rcosN += (p->rcosN % 2)==0; // force rcos imp. length odd
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p->rcosV = cmMemResizeZ(cmSample_t,p->rcosV,p->rcosN); // alloc rcos imp. resp. vector
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p->pnM = cmMemResizeZ(int,p->pnM,p->mlsN*a->chN); // alloc spreading-code mtx
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p->sigN = p->mlsN * a->samplesPerChip; // calc audio signal length
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// generate spreading codes
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if( cmGenGoldCodes(a->lfsrN, a->mlsCoeff0, a->mlsCoeff1, a->chN, p->pnM, p->mlsN ) == false )
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{
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rc = cmCtxRtCondition(&p->obj,cmSubSysFailRC,"Unable to generate sufficient balanced Gold codes.");
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goto errLabel;
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}
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// generate the rcos impulse response
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_cmGoldSigRaisedCos(p->rcosV,p->rcosN,a->samplesPerChip,a->rcosBeta);
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// for each channel
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for(i=0; i<a->chN; ++i)
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{
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// Note: if (i*p->mlsN) is set to 0 in the following line then all channels
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// will use the same spreading code.
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p->ch[i].pnV = p->pnM + (i*p->mlsN); // get ch. spreading code
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p->ch[i].bbV = cmMemResizeZ(cmSample_t,p->ch[i].bbV,p->sigN); // alloc baseband signal vector
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p->ch[i].mdV = cmMemResizeZ(cmSample_t,p->ch[i].mdV,p->sigN); // alloc output audio vector
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// Convolve spreading code with rcos impulse reponse to form baseband signal.
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_cmGoldSigConv(p, i );
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// Modulate baseband signal to carrier frq. and apply attack/decay envelope.
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_cmGoldSigModulate(p, i );
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}
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errLabel:
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if((rc = cmErrLastRC(&p->obj.err)) != cmOkRC )
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cmGoldSigFree(&p);
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return rc;
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}
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cmRC_t cmGoldSigFinal( cmGoldSig_t* p )
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{ return cmOkRC; }
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cmRC_t cmGoldSigWrite( cmCtx* ctx, cmGoldSig_t* p, const char* fn )
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{
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cmVectArray_t* vap = NULL;
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unsigned i;
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vap = cmVectArrayAlloc(ctx,kSampleVaFl);
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for(i=0; i<p->a.chN; ++i)
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{
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cmVectArrayAppendS(vap,p->ch[i].bbV,p->sigN);
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cmVectArrayAppendS(vap,p->ch[i].mdV,p->sigN);
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}
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cmVectArrayWrite(vap,fn);
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cmVectArrayFree(&vap);
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return cmOkRC;
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}
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cmRC_t cmGoldSigGen( cmGoldSig_t* p, unsigned chIdx, unsigned prefixN, unsigned dsN, unsigned *bsiV, unsigned bsiN, double noiseGain, cmSample_t** yVRef, unsigned* yNRef )
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{
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unsigned yN = prefixN + bsiN * (p->sigN + dsN);
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cmSample_t* yV = cmMemAllocZ(cmSample_t,yN);
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unsigned i;
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cmVOS_Random(yV, yN, -noiseGain, noiseGain );
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for(i=0; i<bsiN; ++i)
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{
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bsiV[i] = prefixN + i*(p->sigN + dsN);
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cmVOS_AddVV(yV + bsiV[i], p->sigN, p->ch[chIdx].mdV );
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}
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if( yVRef != NULL )
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*yVRef = yV;
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if( yNRef != NULL )
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*yNRef = yN;
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return cmOkRC;
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}
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69
cmProc5.h
69
cmProc5.h
@ -39,6 +39,75 @@ extern "C" {
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cmRC_t cmGoertzelExec( cmGoertzel* p, const cmSample_t* in, unsigned procSmpCnt, double* outV, unsigned chCnt );
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//=======================================================================================================================
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// Gold Code Signal Generator
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//
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typedef struct
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{
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unsigned chN; // count of channels (each channel has a unique id)
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double srate; // system sample rate (samples/second)
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unsigned lfsrN; // linear feedback shift register (LFSR) length used to form Gold codes
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unsigned mlsCoeff0; // LFSR coeff. 0
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unsigned mlsCoeff1; // LFSR coeff. 1
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unsigned samplesPerChip; // samples per spreading code bit
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double rcosBeta; // raised cosine impulse response beta coeff.
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unsigned rcosOSFact; // raised cosine impulse response oversample factor
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double carrierHz; // carrier frequency
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double envMs; // attack/decay envelope duration
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} cmGoldSigArg_t;
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typedef struct
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{
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int* pnV; // pnV[ mlsN ] spread code (aliased from pnM[:,i])
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cmSample_t* bbV; // bbV[ sigN ] baseband signal at audio rate
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cmSample_t* mdV; // mdV[ sigN ] modulated signal at audio rate
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} cmGoldSigCh_t;
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typedef struct
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{
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cmObj obj; //
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cmGoldSigArg_t a; // argument record
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cmGoldSigCh_t* ch; // ch[ chN ] channel array
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int* pnM; // pnM[mlsN,chN] (aliased to ch[].pnV)
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cmSample_t* rcosV; // rcosV[rcosN] raised cosine impulse response
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unsigned rcosN; // length of raised cosine impulse response
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unsigned mlsN; // length of Gold codes (Maximum length sequence length)
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unsigned sigN; // length of channel signals bbV[] and mdV[]
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} cmGoldSig_t;
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cmGoldSig_t* cmGoldSigAlloc( cmCtx* ctx, cmGoldSig_t* p, const cmGoldSigArg_t* a );
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cmRC_t cmGoldSigFree( cmGoldSig_t** pp );
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cmRC_t cmGoldSigInit( cmGoldSig_t* p, const cmGoldSigArg_t* a );
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cmRC_t cmGoldSigFinal( cmGoldSig_t* p );
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cmRC_t cmGoldSigWrite( cmCtx* ctx, cmGoldSig_t* p, const char* fn );
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// Generate a signal consisting of underlying white noise with
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// bsiN repeated copies of the id signal associated with
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// channel 'chIdx'. Each discrete id signal copy is separated by 'dsN' samples.
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// The signal will be prefixed with 'prefixN' samples of silence (noise).
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// On return sets 'yVRef' to point to the generated signal and 'yNRef'
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// to the count of samples in 'yVRef'.
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// On error sets yVRef to NULL and yNRef to zero.
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// The vector returned in 'yVRef' should be freed via atMemFree().
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// On return sets bsiV[bsiN] to the onset sample index of each id signal copy.
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// The background noise signal is limited to the range -noiseGain to noiseGain.
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cmRC_t cmGoldSigGen(
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cmGoldSig_t* p,
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unsigned chIdx,
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unsigned prefixN,
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unsigned dsN,
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unsigned *bsiV,
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unsigned bsiN,
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double noiseGain,
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cmSample_t** yVRef,
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unsigned* yNRef );
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cmRC_t cmGoldSigTest( cmCtx* ctx );
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#ifdef __cplusplus
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}
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