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158 lines
4.8 KiB
158 lines
4.8 KiB
/**********
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Copyright 1990 Regents of the University of California. All rights reserved.
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Author: 1987 Gary W. Ng
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**********/
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/*
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* NevalSrc (noise, lnNoise, ckt, type, node1, node2, param)
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* This routine evaluates the noise due to different physical
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* phenomena. This includes the "shot" noise associated with dc
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* currents in semiconductors and the "thermal" noise associated with
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* resistance. Although semiconductors also display "flicker" (1/f)
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* noise, the lack of a unified model requires us to handle it on a
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* "case by case" basis. What we CAN provide, though, is the noise
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* gain associated with the 1/f source.
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*/
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#include "ngspice/ngspice.h"
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#include "ngspice/cktdefs.h"
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#include "ngspice/const.h"
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#include "ngspice/noisedef.h"
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void
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NevalSrc (double *noise, double *lnNoise, CKTcircuit *ckt, int type, int node1, int node2, double param)
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{
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double realVal;
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double imagVal;
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double gain;
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realVal = ckt->CKTrhs [node1] - ckt->CKTrhs [node2];
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imagVal = ckt->CKTirhs [node1] - ckt->CKTirhs [node2];
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gain = (realVal*realVal) + (imagVal*imagVal);
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switch (type) {
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case SHOTNOISE:
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*noise = gain * 2 * CHARGE * fabs(param); /* param is the dc current in a semiconductor */
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*lnNoise = log( MAX(*noise,N_MINLOG) );
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break;
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case THERMNOISE:
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*noise = gain * 4 * CONSTboltz * ckt->CKTtemp * param; /* param is the conductance of a resistor */
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*lnNoise = log( MAX(*noise,N_MINLOG) );
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break;
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case N_GAIN:
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*noise = gain;
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break;
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}
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}
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/*
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* NevalSrc2 (noise, lnNoise, ckt, type, node1, node2, param, node3, node4, param2)
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* This routine is a modified version of NevalSrc() that computes
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* the output noise due to two fully-correlated noise sources. It is
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* useful for implementing correlated gate and drain noises in MOSFETs.
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*
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* Like NevalSrc(), it evaluates the noise due to different physical
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* phenomena. This includes the "shot" noise associated with dc
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* currents in semiconductors and the "thermal" noise associated with
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* resistance. Although semiconductors also display "flicker" (1/f)
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* noise, the lack of a unified model requires us to handle it on a
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* "case by case" basis. What we CAN provide, though, is the noise
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* gain associated with the 1/f source.
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*/
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/* Modified by Darsen Lu for BSIM4 tnoiMod=2 10/10/2010
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*/
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void
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NevalSrc2 (
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double *noise,
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double *lnNoise,
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CKTcircuit *ckt,
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int type,
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int node1,
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int node2,
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double param1,
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int node3,
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int node4,
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double param2,
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double phi21) /* Phase of signal 2 relative to signal 1 */
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{
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double realVal1, imagVal1;
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double realVal2, imagVal2;
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double realOut, imagOut, param_gain;
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double T0, T1, T2, T3;
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realVal1 = ckt->CKTrhs [node1] - ckt->CKTrhs [node2];
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imagVal1 = ckt->CKTirhs [node1] - ckt->CKTirhs [node2];
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realVal2 = ckt->CKTrhs [node3] - ckt->CKTrhs [node4];
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imagVal2 = ckt->CKTirhs [node3] - ckt->CKTirhs [node4];
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T0 = sqrt(param1);
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T1 = sqrt(param2);
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T2 = T1 * cos(phi21);
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T3 = T1 * sin(phi21);
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realOut = T0 * realVal1 + T2 * realVal2 - T3 * imagVal2;
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imagOut = T0 * imagVal1 + T2 * imagVal2 + T3 * realVal2;
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param_gain = (realOut*realOut) + (imagOut*imagOut);
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switch (type) {
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case SHOTNOISE:
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*noise = 2.0 * CHARGE * fabs(param_gain); /* param is the dc current in a semiconductor */
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*lnNoise = log( MAX(*noise,N_MINLOG) );
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break;
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case THERMNOISE:
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*noise = 4.0 * CONSTboltz * ckt->CKTtemp * param_gain; /* param is the conductance of a resistor */
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*lnNoise = log( MAX(*noise,N_MINLOG) );
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break;
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case N_GAIN:
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*noise = 0.0;
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break;
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}
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}
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/*
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PN 2003:
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The following function includes instance dtemp in
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thermal noise calculation.
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It will replace NevalSrc as soon as all devices
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will implement dtemp feature.
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*/
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void
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NevalSrcInstanceTemp (double *noise, double *lnNoise, CKTcircuit *ckt, int type,
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int node1, int node2, double param, double param2)
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{
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double realVal;
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double imagVal;
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double gain;
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realVal = ckt->CKTrhs [node1] - ckt->CKTrhs [node2];
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imagVal = ckt->CKTirhs [node1] - ckt->CKTirhs [node2];
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gain = (realVal*realVal) + (imagVal*imagVal);
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switch (type) {
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case SHOTNOISE:
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*noise = gain * 2 * CHARGE * fabs(param); /* param is the dc current in a semiconductor */
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*lnNoise = log( MAX(*noise,N_MINLOG) );
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break;
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case THERMNOISE:
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*noise = gain * 4 * CONSTboltz * (ckt->CKTtemp + param2) /* param2 is the instance temperature difference */
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* param; /* param is the conductance of a resistor */
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*lnNoise = log( MAX(*noise,N_MINLOG) );
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break;
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case N_GAIN:
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*noise = gain;
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break;
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}
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}
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