Background simulation of the Spectre

Dear all,

I am using the Spectre simulator to simulate the VCO. Now, I am using the Parametric Analysis function to simulate the tuning frequency range of the VCO (vary the Vctrl of the varactor). Actually, I want to simulate it in the background simulation. I have tried to run the script of the "runSimulation". It just run one times only and will not run the no. of the run I set in the Parametric Analysis.

Therefore, how could I run the Parametric Analysis in the background simulation?

Thanks

wccheng