[SI-LIST] Re: HSpice implementation of recursive convolution
- From: Raymond Anderson <raymond.anderson@xxxxxxx>
- To: piesiewicz@xxxxxxxxxxxxx
- Date: Tue, 02 Sep 2003 14:53:28 -0700
Equations may be evaluated within an Hspice deck at runtime by defining
the equations within a .param statement.
Here is a snippet from an Hspice deck showing a number of component
values being calculated by way of equations at runtime:
.param pi2='2*3.14159'
.param c1=1uF
.param r1='1/(pi2*fI*c1)'
.param r2='1/(pi2*z1*c1)'
.param r3='pi2*z2*r1/(pi2*p1-pi2*z2)'
.param c2='1/(pi2*z2*(r1+r3))'
.param c3='1/(pi2*p2*r2)'
I haven't looked into the details of your code, but the general
implementation might look something like this:
.param v = 'Vtran(n1) - Vtran(n2)'
.param x = 'x+theta*v'
.param x = 'exp(p_1*dt)*x+ exp(p_1*dt-1)*v'
.param i_eq = 'k_11*x'
Hopefully this gives you a starting point.
BTW, the 'S element' in the recent versions of Hspice utilizes
recursive convolution internally when doing time domain simulation
of s-parameter defined transfer functions.
-Ray Anderson
Sun Microsystems Inc.
Radoslaw Piesiewicz wrote:
> Hi,
> I have a problem, namely how to implement the following code (it is
> recursive convolution) in HSpice, the code is from some simulator that works
> similarly to HSpice. The problem is to calculate the current Curr, it is done
> in two step process
> at every step in the transient analysis (at the intervals of FIXED
> parameter). The problem is in implementing the part CALC ... ENDCALC
>
> Thanks
>
> Code:
>
> Var k_11 1.0G
> Var p_1 -5.0G
> Var dt 2p
> Var theta FUNC=(p_1**2+exp(p_1*dt))
> Var x=0
> Var i_eq 0
> Var v=0
>
> Res 'portVCCS' n1 n2 1.0 G=k_11*theta
> Curr 'portCurr' n1 n2 TRAN=i_eq
>
> Cap 'Cload' n2 GND 1p
>
> Volt 'Vin' n1 GND TRAN=1*(t>0)
>
> Sweep ''
> + LOOP 1001 TIME LIN 0 2n FIXED
> + X 't' 's' 0 2n MULTX='n'
> + Y 'u_(out)' 'V' 0 2
>
> CALC
>
> v = Vtran(n1) - Vtran(n2)
> x= x+theta*v
> x= exp(p_1*dt)*x+ exp(p_1*dt-1)*v
> i_eq=k_11*x
>
> ENDCALC
>
> Show Y Vtran(n2)
>
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> - - - - - - - - - - - - -
> Dipl.-Ing. Radoslaw Piesiewicz
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