module V_t_ff(q,clk);
 input clk;
 output q;
 voltage q,clk;
 parameter real tdelay   = 5n from [0:inf),
                ttransit = 5n from [0:inf),
                vout_high = 5,
                vout_low  = 0 from (-inf:vout_high),
                vth       = 1.4;
 parameter integer q_init = 0 from [0:1];

 integer x;
 analog
 begin
   @(initial_step) x = q_init;

   @(cross(V(clk) - vth, +1 )) x = !x;

   V(q)    <+ transition( vout_high*x  + vout_low*!x, tdelay, ttransit );
 end
endmodule