Patent ID: 8593216

Claim:
An apparatus comprising: a first signal path including a first transfer function circuit to provide a control signal for a first terminal of a resonator tank circuit of a VCO circuit and configured to receive a first signal and to perform the first transfer function on the first signal; a second signal path including a second transfer function circuit and configured to receive a second signal and to perform the second transfer function on the second signal, the second signal is a scaled version of the first signal by a factor and the second signal path includes at least one component scaled smaller by the factor; a summing circuit including a non-unity gain configured operational amplifier (op-amp) coupled to the first and second signal paths and the op-amp configured to sum output signals from the first and second signal paths to generate the control signal having op-amp noise; and a noise cancellation path coupled between the output signal of the second signal path and a second terminal of the resonator tank circuit and configured to provide a noise cancellation signal used to cancel the op-amp noise in the control signal.