112 and v 2 on line 114 are nominally phase shifted by 180 degrees and each are ideally sinusoidal in nature the dc voltage component of v 2 on line 114 is compared to a bias voltage on line 132 by the amplifier a 2 130 in various embodiments other voltages can be compared to the bias voltage on line 132 for example the dc component of the signal v 1 on line 112 can be compared in other embodiments the resistor r 1 120 is a number of resistors in series and a voltage at a node between two of these resistors can be compared to the bias voltage on line 132 in a specific embodiment of the present invention the bias voltage on line 132 is set to a ground referenced voltage that is equal to one half a minimum supply voltage for the oscillator in other embodiments of the present invention this bias voltage may be equal to a reference voltage for example the bias voltage on line 132 may be equal to a bandgap voltage in other embodiments of the present invention the bias voltage may be a function of vcc temperature or other condition alternately the bias voltage on line 132 may be independent of.