| 摘要 |
A controlled oscillator generates an output signal having a frequency that is controllable by an input signal. The oscillator includes a switchable variable capacitor arrangement for tuning an output frequency of the controlled oscillator; and circuitry that, in combination with the switchable variable capacitor arrangement, generates an oscillating signal whose frequency is, at least in part, a function of a total capacitance of the switchable variable capacitor arrangement. The switchable variable capacitor arrangement includes a plurality of variable capacitors, each tunable by means of a tuning control signal and a switch arrangement that selectively opens or closes electrical paths to one or more of the variable capacitors under the control of one or more switch control signals, wherein the number of variable capacitors that contribute to the total capacitance of the switchable variable capacitor arrangement is controlled by states of the one or more switch control signals. |
