module: dsynth_truncate
parameters: int frac
inputs: double in
outputs: double out
static_variables: double in_abs double out_abs double factor 
init:
in_abs=0;
factor=pow(2,frac);
code:
 if(in>=0.0)
   {out=((floor)(in*factor))/factor;}
 else
   {out=((floor)(in*factor))/factor;}
