Envelop Analysis in SpectreRF with frequency divider

Hello, I encoutered a problem when simulating a circuit that contains a freuency divider using the Envelop Analysis in spectreRF. I have taken the following step:
1. The "oversample factor" is set to be 2 because the divider halven the input frequency
2. The "freqdivide" in the option form was set to be 2 correspondingly.
3. The other settings are the same as simulating without a divider
Now, when I try to analyze its output spectrem, the result is very weird......
Can anybody give some tips on it?
Thanks!

not sure exactly what an oversample factor is in spectre, but if it means the fourier frequency of analysis, use a factor of 5 or 10 and you will get better results. Remember, the output is a rectangular wave (lots of harmonics).

Thanks～
I used the HB to simulate the circuit.

[quote="yjzhang"]Use Envelope Analysis based on Shooting Newton not HB.