Ring oscillator and means for controlling the frequency thereof

摘要

A ring oscillator according to the invention comprises a closed chain of at least two modules (1, 2). At least one of the modules (1, 2) comprises a primary (10) and a second amplifier stage (11) and combination means (12) for combining output signals of the primary (10) the secondary amplifier stage (11) so as to generate an output signal of the module. The amplifier stages (10, 11) have a mutually different delay and the primary (10) and the secondary am amplifier stage (11) are each coupled to an input (13) of the module (1). The ring oscillator further comprises a control unit (4) for generating a first (C1) and a second auxiliary control signal (C2) for controlling the amplification of the primary amplifier stage (10) and the secondary amplifier stage (11) in response to an input control signal (Co) representative for a desired frequency for the ring oscillator. The ring oscillator according to the invention is in particular suitable for application in a data and clock recovery unit (DCR), for example in a receiver for a transmission channel and a device fair reproducing an information carrier.