Patent ID: 6313962
Filing Date: 2001-11-06
Classification: G11B,H03L

Abstract:
A combined voltage controlled oscillator, comprising:an oscillator providing an output signal having a frequency that varies proportionately to an oscillator input signal; andan adjustable voltage source, the adjustable voltage source having a first configuration for a write mode and a second configuration for a read mode, and the adjustable voltage source providing the oscillator input signal to the oscillator in response to receiving an input current signal, the adjustable voltage source further comprising a first and second capacitor coupled in series and a switch coupled across the second capacitor, the switch being open to provide the first configuration and closed to provide the second configuration;a transconductance amplifier for receiving the input signal from the adjustable voltage source and converting the input signal to a current signal having a first current value;a current modifier, the current modifier providing a current phase signal according to whether a write or a read mode is selected and whether an acquisition or track mode is selected; andan adder coupled to the transconductance amplifier and the current modifier, the adder modifying the current signal according to the current phase signal to produce an adjusted current signal;wherein the oscillator comprises a current controlled oscillator coupled to the adder, the current controlled oscillator receiving the adjusted current signal and producing an output signal having a frequency proportional to a magnitude of the current of the adjusted current signal.