Hi Everyone,

I am simulating(using HSPICE) HR neuron model using analog computer technique but I am not getting the required response. If anyone can figure out what might be the problem , I will be extremely thankful.
I am using ALM124 model of opamp and MLT04 model of multiplier.
Code:

***HR***

Vdd 100 0 DC 10
Vss 99 0 DC -10
Vconst 7 0 1.5
Vbias1 1 0 DC 1
Vbias2 12 0 DC 1
Vbias3 14 0 DC 1
Vbias4 4 0 DC 1
Vref1 15 0 -1
Vref2 16 0 1


.options post
.tran 1m 500m

X1 1 2 3 100 99 ALM124
RxI 7 2 873k
Rxy 8 2 110k
Rxz 9 2 330k
Rxx2 10 2 611
Rxx3 11 2 15
Cx 2 3 0.01uF ic=0

X4 4 5 6 100 99 ALM124
R1 3 5 10k
R2 5 6 10k

X5 3 3 0 20 100 99 MLT04
X6 20 3 0 21 100 99 MLT04
E1 10 0 20 0 2.5
*As output of MLT04 Vout=0.4Vin^2 , so output is amplified to get Vout=Vin^2
E2 11 0 21 0 -6.25
*As output of Cubic Generator is Vout= 0.16Vin^3 , so output is amplified and inverted to get Vout=-Vin^3



X2 12 13 8 100 99 ALM124
Ryy 8 13 22k
Ryx2 10 13 73
Rye 15 13 522.8k
Cy 13 8 0.1uF ic=0

X3 14 15 9 100 99 ALM124
Rzz 9 15 10.5k
Rzx 6 15 1.8k
Rzh 16 15 13.2k
Cz 16 15 100uF ic=0



 .MODEL ALM124 AMP
 +       C2=  30.00P     SRPOS=   .5MEG      SRNEG= .5MEG
 +       IB=  45N         IBOS=   3N           VOS=  4M
 +     FREQ=  1MEG      DELPHS=   25          CMRR=  85
 +     ROUT=  50            AV=   100K         ISC=  40M
 +    VOPOS=  9.5      VONEG=   -9.5        PWR=  142M
 +      VCC=  10           VEE=   -10         TEMP=  25.00
 +     PSRR=  100          DIS=   8.00E-16     JIS=  8.00E-16




* MLT04 SPICE Macro-model Rev. A, 12/93
* JCB / ADI
*
* Copyright 1993 by Analog Devices
*
* Refer to "README.DOC" file for License Statement. Use of
* this model indicates your acceptance of the terms and pro-
* visions in the License Statement.
*
* Node assignments
* X-input
* | Y-input
* | | Ground
* | | | W-output
* | | | | Positive supply
* | | | | | Negative supply
* | | | | | |
.SUBCKT MLT04 3 4 2 1 99 50
*
* X AND Y INPUT STAGES
*
V1 3 20 10.5E-3
C1 20 2 3E-12
R1 20 2 1E6
I1 20 2 2.3E-6
V2 4 21 10.5E-3
C2 21 2 3E-12
R2 21 2 1E6
I2 21 2 2.3E-6
*
* MULTIPLIER CORE
*
G1 98 22 POLY(2) (20,2) (21,2) (0,0,0,0,0.4E-6)
R3 98 22 1E6
C3 98 22 1E-15
*
* INPUT STAGE
*
I3 99 28 1E-4
Q1 24 1 26 QP
Q2 25 23 27 QP
R4 50 24 11635
R5 50 25 11635
R6 26 28 11119
R7 27 28 11119
E1 23 98 POLY(1) (22,98) -10E-3 1
*
* GAIN STAGE AND DOMINANT POLE AT 145HZ
*
EREF 98 0 POLY(2) (99,0) (50,0) 0 0.5 0.5
G2 98 29 (24,25) 8.59E-5
R8 29 98 5.82E8
C4 29 98 1.89E-12
D1 29 30 DX
D2 31 29 DX
V3 99 30 2.2
V4 31 50 2.2
*
*POLE AT 30MHZ
*
G3 98 32 (29,98) 1E-6
R9 32 98 1E6
C5 32 98 5.31E-15
*
* OUTPUT STAGE
*
R10 99 1 80
R11 1 50 80
G4 1 99 (99,32) 12.5E-3
G5 50 1 (32,50) 12.5E-3
D3 32 33 DX
D4 34 32 DX
V5 33 1 0.72
V6 1 34 0.72
G6 98 35 (1,32) 12.5E-3
D5 35 36 DX
D6 37 35 DX
V7 36 98 DC 0
V8 98 37 DC 0
F1 99 50 POLY(2) V7 V8 3.65E-3 1 1
*
* MODELS USED
*
.MODEL DX D
.MODEL QP PNP(BF=143)
.ENDS      

.end