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

Stephen R. Whiteley 2019-06-03