loaded down by the vco 10 one skilled in the art would understand that any high impedance path may be used in place of resistors 130 135 the two capacitors 140 145 which are dc blocking capacitors may be used to prevent current from being injected into the vco 10 from the tuning voltage source one skilled in the art would understand that any dc blocking path may be used in place of capacitors 140 145 additionally in one embodiment each of the varactor pairs 110 120 may include a bias voltage v cm1 v cm2 the bias voltage can be chosen to adjust capacitance over voltage characteristic of the varactor pairs 110 120 in one embodiment each of the varactors vc 1 vc 2 vc 3 vc 4 may be implemented with a metal oxide semiconductor field effect transistor mosfet having its drain tied its source each of the varactor pairs 110 120 may comprise two mosfets connected in series at the drain source connection each of the varactors pairs 110 120 may be biased by applying a voltage to the common drain source connection the tuning voltage may be applied to the gate of each mosfet through respective input resistors 130 135 since the vco frequency depends inversely on the square root of the product of inductance and varactor capacitance and since the inductance of inductor 150 is fixed then as the capacitance of.