what determines the oscillating frequency of DRO?

Hi all,
I found when simulating with ADS, the oscillating freq changes when impedance-matching circuits change without chaning DR setting ?Can anybody
tell me the reason?Thanks.

Yun

Many factors can change the DRO freq, when impedance-matching changes, the osc mode or osc condition changes, so the freq changes.
The model of DRO is RLC parralel. So impedance changes, the LC of the model changes, so the freq changes.

Using a buffer stage between the DRO and the circuit its driving will isolate it considerably from external infulences

As with all free running oscillators, just adding a load will cause a freq shift.

Dave