module vco(in,out);
 input in;
 output out;
 voltage in,out;
 // SJM added
 voltage vin;

 parameter real f0 = 1.0M from (0:inf), // center frequency
                kf = 100K,              // frequency coefficient Hz/V
                lockrange = 3,          // lockrange according input voltage
                vin_offset = 0,         // input dc offset, e.g.  V(in)=vin_offs et -> f0
                vout_offset = 0,        // output dc offset
                vout_mag = 1,           // output magnitude
                phi0 = 0;               // dc phase, given in radian

 real w;

 analog
 begin
   vin = V(in) - vin_offset;
   if (vin > lockrange)    vin = lockrange;
   else
     if (vin < -lockrange) vin = -lockrange;

   w = `M_TWO_PI * (f0 + kf*vin);
   V(out) <+ vout_offset + vout_mag*sin(w*$realtime + phi0);
 end
endmodule