free running vco

this is the frequency , which will be out of the VCO without applying the control voltage ,


khouly

It's the frequency of the VCO outside of a PLL, yes I agree, it is the oscillation frequency when there is not a control voltage.

VCO can have a control voltage and still be un-locked. Steering a VCO with a voltage from say a variable bench PSU does not make it locked. I would say free-running is anything outside the closed PLL loop. A loop can be opened and the control voltage can go either pin high or low, depending on the design.

Wording from a patent document

Thank you everyone

it's the VCO running stand alone ( not in closed loop with a PLL )

The VCO is not in PLL closed loop, I think.

it means VCO runs without PLL.