module V_log_amp(in,out);
 input in;
 output out;
 voltage in,out;

 parameter real vin_offset = 0,         // input dc offset
                vout_offset= 0,         // output dc offset
                gain       = 1,         // amplifier gain
                min_arg = 1.0e-9 from (0:inf);
                                        // minimum arg for log function

 real log_vin_min,vin;

 analog
 begin
   @(initial_step) log_vin_min = log(min_arg);

   vin = abs(V(in)-vin_offset);
   if (vin < vin_min) vin = log_vin_min;
   else               vin = log(vin);

   V(out) <+ gain * vin + vout_offset;
 end
endmodule