module: vco
parameters: double freq double kvco
inputs:  double vctrl
outputs:  double_interp squareout double sineout
static_variables:
classes:  Vco vco("fc + Kv*x","fc,Kv,Ts",freq,kvco,Ts);
init: 
code:
vco.inp(vctrl);
squareout = vco.out;
sineout = sin(vco.phase);
