Patent ID: 6388536
Filing Date: 2002-05-14
Classification: H03B,H03D,H03L

Abstract:
A frequency synthesizer having at least one variable frequency output, the output frequency varying as a capacitance within the synthesizer varies, comprising:a discretely variable capacitance circuit integrated within the frequency synthesizer and having a first control signal, the first control signal determining which of a plurality of discrete capacitance amounts are included within an overall capacitance for the discretely variable capacitance circuit; a continuously variable capacitance circuit integrated within the frequency synthesizer and having a second control signal, the capacitance amount for the continuously variable capacitance circuit comprising a plurality of continuous capacitance amounts from a plurality of capacitance circuits, and the second control signal comprising a plurality of variable control signals that determine how much capacitance from each of the plurality of capacitance circuits are included within an overall capacitance for the continuously variable capacitance circuit, such that a relatively linear circuit behavior for the continuously variable capacitance circuit is achieved over a selected frequency range; and frequency control circuitry to coarsely tune the output frequency by adjusting the first control signal and to finely tune the output frequency by adjusting the second control signal.