diff --git a/src/spicelib/analysis/noisesp.c b/src/spicelib/analysis/noisesp.c
new file mode 100644
index 000000000..2f8f38c3b
--- /dev/null
+++ b/src/spicelib/analysis/noisesp.c
@@ -0,0 +1,371 @@
+/**********
+Copyright 1990 Regents of the University of California.  All rights reserved.
+Author: 1987 Gary W. Ng
+Modified: 2001 AlansFixes
+**********/
+
+/* Patch to noisean.c by Richard D. McRoberts.
+ * Patched with modifications from Weidong Liu (2000)
+ * Patched with modifications ftom Weidong Liu
+ * in bsim4.1.0 code
+ */
+
+#include "ngspice/ngspice.h"
+#include "ngspice/acdefs.h"
+#include "ngspice/cktdefs.h"
+#include "ngspice/iferrmsg.h"
+#include "ngspice/cpextern.h"
+#include "ngspice/noisedef.h"
+#include "ngspice/sperror.h"
+#include "ngspice/sim.h"
+#include "vsrc/vsrcdefs.h"
+#include "isrc/isrcdefs.h"
+
+// fixme
+//   ugly hack to work around missing api to specify the "type" of signals
+extern int fixme_onoise_type;
+extern int fixme_inoise_type;
+
+#ifdef RFSPICE
+
+int
+NOISEsp (CKTcircuit *ckt, int restart)
+{
+    /* variable must be static, for continuation of interrupted (Ctrl-C),
+    longer lasting noise anlysis */
+    static Ndata *data;
+
+    double realVal;
+    double imagVal;
+    int error;
+    int posOutNode;
+    int negOutNode;
+    int step;
+    IFuid freqUid;
+    double freqTol; /* tolerence parameter for finding final frequency; hack */
+    int i, src_type;
+
+    NOISEAN *job = (NOISEAN *) ckt->CKTcurJob;
+    GENinstance *inst = CKTfndDev(ckt, job->input);
+    bool frequequal = AlmostEqualUlps(job->NstartFreq, job->NstopFreq, 3);
+
+    posOutNode = (job->output) -> number;
+    negOutNode = (job->outputRef) -> number;
+
+    if (job->NnumSteps < 1) {
+        SPfrontEnd->IFerrorf(ERR_WARNING,
+                             "Number of steps for noise measurement has to be larger than 0,\n    but currently is %d\n",
+                             job->NnumSteps);
+        return(E_PARMVAL);
+    } else if ((job->NnumSteps == 1) && (job->NstpType == LINEAR)) {
+        if (!frequequal) {
+            job->NstopFreq = job->NstartFreq;
+            SPfrontEnd->IFerrorf(ERR_WARNING,
+                                 "Noise measurement at a single frequency %g only!\n",
+                                 job->NstartFreq);
+        }
+    } else {
+        if (frequequal) {
+            job->NstopFreq = job->NstartFreq;
+            job->NnumSteps = 1;
+            SPfrontEnd->IFerrorf(ERR_WARNING,
+                                 "Noise measurement at a single frequency %g only!\n",
+                                 job->NstartFreq);
+        }
+    }
+    /* see if the source specified is AC */
+    {
+        bool ac_given = FALSE;
+
+        if (!inst || inst->GENmodPtr->GENmodType < 0) {
+            SPfrontEnd->IFerrorf (ERR_WARNING,
+                                  "Noise input source %s not in circuit",
+                                  job->input);
+            return E_NOTFOUND;
+        }
+
+        if (inst->GENmodPtr->GENmodType == CKTtypelook("Vsource")) {
+            ac_given = ((VSRCinstance *)inst) -> VSRCacGiven;
+            src_type = SV_VOLTAGE;
+        } else if(inst->GENmodPtr->GENmodType == CKTtypelook("Isource")) {
+            ac_given = ((ISRCinstance *)inst) -> ISRCacGiven;
+            src_type = SV_CURRENT;
+        } else {
+            SPfrontEnd->IFerrorf (ERR_WARNING,
+                                  "Noise input source %s is not of proper type",
+                                  job->input);
+            return E_NOTFOUND;
+        }
+
+        if (!ac_given) {
+            SPfrontEnd->IFerrorf (ERR_WARNING,
+                                  "Noise input source %s has no AC value",
+                                  job->input);
+            return E_NOACINPUT;
+        }
+    }
+
+    if ( (job->NsavFstp == 0.0) || restart) { /* va, NsavFstp is double */
+        switch (job->NstpType) {
+
+
+        case DECADE:
+            job->NfreqDelta = exp(log(10.0)/
+                                  job->NnumSteps);
+            break;
+
+        case OCTAVE:
+            job->NfreqDelta = exp(log(2.0)/
+                                  job->NnumSteps);
+            break;
+
+        case LINEAR:
+            if (job->NnumSteps == 1)
+                job->NfreqDelta = 0;
+            else
+                job->NfreqDelta = (job->NstopFreq -
+                                   job->NstartFreq) / (job->NnumSteps - 1);
+            break;
+
+        default:
+            return(E_BADPARM);
+        }
+
+        /* error = DCop(ckt); */
+        error = CKTop(ckt, (ckt->CKTmode & MODEUIC) | MODEDCOP | MODEINITJCT,
+                      (ckt->CKTmode & MODEUIC) | MODEDCOP | MODEINITFLOAT,
+                      ckt->CKTdcMaxIter);
+
+        if (error) return(error);
+
+        /* Patch to noisean.c by Richard D. McRoberts. */
+        ckt->CKTmode = (ckt->CKTmode & MODEUIC) | MODEDCOP | MODEINITSMSIG;
+        error = CKTload(ckt);
+        if(error) return(error);
+
+        data = TMALLOC(Ndata, 1);
+        step = 0;
+        data->freq = job->NstartFreq;
+        data->outNoiz = 0.0;
+        data->inNoise = 0.0;
+        data->squared = cp_getvar("sqrnoise", CP_BOOL, NULL, 0) ? 1 : 0;
+
+        /* the current front-end needs the namelist to be fully
+           declared before an OUTpBeginplot */
+
+        SPfrontEnd->IFnewUid (ckt, &freqUid, NULL, "frequency", UID_OTHER, NULL);
+
+        data->numPlots = 0;                /* we don't have any plots  yet */
+        error = CKTnoise(ckt,N_DENS,N_OPEN,data);
+        if (error) return(error);
+
+        /*
+         * all names in the namelist have been declared. now start the
+         * plot
+         */
+
+        if (src_type == SV_VOLTAGE)
+            fixme_inoise_type =
+                data->squared ? SV_SQR_VOLTAGE_DENSITY : SV_VOLTAGE_DENSITY;
+        else
+            fixme_inoise_type =
+                data->squared ? SV_SQR_CURRENT_DENSITY : SV_CURRENT_DENSITY;
+
+        fixme_onoise_type =
+            data->squared ? SV_SQR_VOLTAGE_DENSITY : SV_VOLTAGE_DENSITY;
+
+        if (!data->squared)
+            for (i = 0; i < data->numPlots; i++)
+                data->squared_value[i] =
+                    ciprefix("inoise", data->namelist[i]) ||
+                    ciprefix("onoise", data->namelist[i]);
+
+        error = SPfrontEnd->OUTpBeginPlot (ckt, ckt->CKTcurJob,
+                                           data->squared
+                                           ? "Noise Spectral Density Curves - (V^2 or A^2)/Hz"
+
+                                           : "Noise Spectral Density Curves",
+                                           freqUid, IF_REAL,
+                                           data->numPlots, data->namelist, IF_REAL,
+                                           &(data->NplotPtr));
+        if (error) return(error);
+
+        if (job->NstpType != LINEAR) {
+            SPfrontEnd->OUTattributes (data->NplotPtr, NULL, OUT_SCALE_LOG, NULL);
+        }
+
+    } else {   /* we must have paused before.  pick up where we left off */
+        step = (int)(job->NsavFstp);
+        switch (job->NstpType) {
+
+        case DECADE:
+        case OCTAVE:
+            data->freq = job->NstartFreq * exp (step *
+                                                log (job->NfreqDelta));
+            break;
+
+        case LINEAR:
+            data->freq = job->NstartFreq + step *
+                         job->NfreqDelta;
+            break;
+
+        default:
+            return(E_BADPARM);
+
+        }
+        job->NsavFstp = 0;
+        data->outNoiz = job->NsavOnoise;
+        data->inNoise = job->NsavInoise;
+        /* saj resume rawfile fix*/
+        error = SPfrontEnd->OUTpBeginPlot (NULL, NULL,
+                                           NULL,
+                                           NULL, 0,
+                                           666, NULL, 666,
+                                           &(data->NplotPtr));
+        /*saj*/
+    }
+
+    switch (job->NstpType) {
+    case DECADE:
+    case OCTAVE:
+        freqTol = job->NfreqDelta * job->NstopFreq * ckt->CKTreltol;
+        break;
+    case LINEAR:
+        freqTol = job->NfreqDelta * ckt->CKTreltol;
+        break;
+    default:
+        return(E_BADPARM);
+    }
+
+    data->lstFreq = data->freq;
+
+    /* do the noise analysis over all frequencies */
+
+    while (data->freq <= job->NstopFreq + freqTol) {
+        if(SPfrontEnd->IFpauseTest()) {
+            job->NsavFstp = step;   /* save our results */
+            job->NsavOnoise = data->outNoiz; /* up until now     */
+            job->NsavInoise = data->inNoise;
+            return (E_PAUSE);
+        }
+        ckt->CKTomega = 2.0 * M_PI * data->freq;
+        ckt->CKTmode = (ckt->CKTmode & MODEUIC) | MODEAC | MODEACNOISE;
+        ckt->noise_input = inst;
+
+        /*
+         * solve the original AC system to get the transfer
+         * function between the input and output
+         */
+
+        NIacIter(ckt);
+        realVal = ckt->CKTrhsOld [posOutNode]
+                  - ckt->CKTrhsOld [negOutNode];
+        imagVal = ckt->CKTirhsOld [posOutNode]
+                  - ckt->CKTirhsOld [negOutNode];
+        data->GainSqInv = 1.0 / MAX(((realVal*realVal)
+                                     + (imagVal*imagVal)),N_MINGAIN);
+        data->lnGainInv = log(data->GainSqInv);
+
+        /* set up a block of "common" data so we don't have to
+         * recalculate it for every device
+         */
+
+        data->delFreq = data->freq - data->lstFreq;
+        data->lnFreq = log(MAX(data->freq,N_MINLOG));
+        data->lnLastFreq = log(MAX(data->lstFreq,N_MINLOG));
+        data->delLnFreq = data->lnFreq - data->lnLastFreq;
+
+        if ((job->NStpsSm != 0) && ((step % (job->NStpsSm)) == 0)) {
+            data->prtSummary = TRUE;
+        } else {
+            data->prtSummary = FALSE;
+        }
+
+        /*
+        data->outNumber = 1;
+        */
+
+        data->outNumber = 0;
+        /* the frequency will NOT be stored in array[0]  as before; instead,
+         * it will be given in refVal.rValue (see later)
+         */
+
+        NInzIter(ckt,posOutNode,negOutNode);   /* solve the adjoint system */
+
+        /* now we use the adjoint system to calculate the noise
+         * contributions of each generator in the circuit
+         */
+
+        error = CKTnoise(ckt,N_DENS,N_CALC,data);
+        if (error) return(error);
+        data->lstFreq = data->freq;
+
+        /* update the frequency */
+
+        switch (job->NstpType) {
+
+        case DECADE:
+        case OCTAVE:
+            data->freq *= job->NfreqDelta;
+            break;
+
+        case LINEAR:
+            data->freq += job->NfreqDelta;
+            break;
+
+        default:
+            return(E_INTERN);
+        }
+        step++;
+
+        if ((job->NnumSteps == 1) && (job->NstpType == LINEAR))
+            break;
+    }
+
+    error = CKTnoise(ckt,N_DENS,N_CLOSE,data);
+    if (error) return(error);
+
+    data->numPlots = 0;
+    data->outNumber = 0;
+
+    if (job->NstartFreq != job->NstopFreq) {
+        error = CKTnoise(ckt,INT_NOIZ,N_OPEN,data);
+
+        if (error) return(error);
+
+        if (src_type == SV_VOLTAGE)
+            fixme_inoise_type =
+                data->squared ? SV_SQR_VOLTAGE : SV_VOLTAGE;
+        else
+            fixme_inoise_type =
+                data->squared ? SV_SQR_CURRENT : SV_CURRENT;
+
+        fixme_onoise_type =
+            data->squared ? SV_SQR_VOLTAGE : SV_VOLTAGE;
+
+        if (!data->squared)
+            for (i = 0; i < data->numPlots; i++)
+                data->squared_value[i] =
+                    ciprefix("inoise", data->namelist[i]) ||
+                    ciprefix("onoise", data->namelist[i]);
+
+        SPfrontEnd->OUTpBeginPlot (ckt, ckt->CKTcurJob,
+                                   data->squared
+                                   ? "Integrated Noise - V^2 or A^2"
+                                   : "Integrated Noise",
+                                   NULL, 0,
+                                   data->numPlots, data->namelist, IF_REAL,
+                                   &(data->NplotPtr));
+
+        error = CKTnoise(ckt,INT_NOIZ,N_CALC,data);
+        if (error) return(error);
+
+        error = CKTnoise(ckt,INT_NOIZ,N_CLOSE,data);
+        if (error) return(error);
+    }
+
+    FREE(data);
+    return(OK);
+}
+
+#endif
\ No newline at end of file