WRspice jj qp modulation demo
*
* The rtype=4 option of the Josephson model causes the gap potential
* to scale with the external "control current" absolute value. For
* unit control current (1 Amp) or larger, the full potential is used,
* otherwise it scales linearly to zero. The transfer function is defined
* externally with controlled sources, as below. The approximation
* Vg = Vg0*(1-t**4) is pretty good, except near t = 1 (T = Tc, t = T/Tc).
* The actual transfer function is left to the user - in the example below,
* the ambient temperature is 7K, Tc=9.2K, and 1mv of "input" causes 1K
* temperature shift.
*
* For amusement, change cct=1 to cct=0 below. This runs much more quickly
* as critical current is set to zero.
*
b1 1 0 jj1 control=v2
v1 2 0 pulse(0 35m 10p 10p)
r1 2 1 100
*
v2 3 0
g1 3 0 4 0 function 1 - (1000*x+7)/9.2)^4
v4 4 0 pulse(-1m 1m 10p 10p 10p 20p 60p)
*
*Nb 1000 A/cm2 area = 30 square microns
.model jj1 jj(rtype=4,cct=1,icon=10m,vg=2.8m,delv=.1m,
+ icrit=0.3m,r0=100,rn=5.4902,cap=1.14195p)
.tran 1p 500p uic
* type "run", then plot v(1) and v(4) to see the gap shift and input
.end