Injection coupled Quadrature VCO - measuring the relative phase between the two quadrature outputs

Hi All,

I am trying to simulate a 3.6GHz injection coupled quadrature VCO. I would like to measure the relative phase between the two quadrature outputs. It can be noticed from literature that based on the topology used, coupling mechanism, couplign strength etc the relative phase difference between the two quadrature outputs can be either  +90degrees or -90degrees. 

during the design process while running PSS i have noticed that the phase difference is interchanging in the PSS solution. It is at times 90 degrees and at times -90 degrees. Since certain quadrature VCOs are know to have the possibility of oscillating with either of the phase differences I wanted to device a force start mechanism to make sure the phase difference is always the same and not varying. 

In order to have a known phase difference, one method i tried and seemed to work is to start one of the coupled oscillators before the other. I am doing this by switching on the bias current source of one of them after the other. This bias switching and settling is a slow process, takes about 10u sec. So over all i need to run the entire simulation for about 15u sec. Doing a transient is taking very long time ( i also need to run this across pvt corners, monte carlo sims etc) So i would like to know if there is a faster way to do the simulations and still get accurate results for the relative phase difference that i am trying to measure.

Thank you,

Vijay