Patent ID: 6760575
Filing Date: 2004-07-06
Classification: H03B,H03J,H03L

Abstract:
Controllable oscillator circuitry having an output frequency dependent upon a variable capacitance amount, comprising:a plurality of different analog control signals, the different analog control signals being dependent upon a phase difference between at least one signal that is related to the output frequency and at least one reference signal; a variable capacitance circuit integrated within the controllable oscillator and configured to receive the plurality of different analog control signals; and a plurality of non-linear capacitor circuits within the variable capacitance circuit configured to provide a combined capacitance amount that contributes at least part of the variable capacitance amount, the non-linear capacitor circuits being configured to be continuously variable between at least two capacitance amounts and each comprising at least one capacitor and at least one variable resistance element having a control node, each control node of the variable resistance elements concurrently receiving at least one of the different analog control signals to determine the capacitance amount contributed by the non-linear capacitance circuit to the combined capacitance amount and thereby to adjust the output frequency up or down.