Patent ID: 7453958

Claim:
A device for extracting a clock frequency underlying a data stream, wherein the data stream comprises a first data pattern at regular first temporal intervals specified with a relative first accuracy, and wherein the data stream further comprises a second data pattern comprising a plurality of clock periods with the clock frequency or a multiple of the clock frequency, wherein the clock periods are specified with a second relative accuracy smaller than the first relative accuracy, comprising: controller for controlling a controllable oscillator for providing an oscillator clock with an oscillator clock frequency, wherein the controller for controlling comprises both a first digital/analog converter and a second digital/analog converter and a summer, coupled to the outputs of the first digital/analog converter and the second digital/analog converter and implemented in order to provide a control signal for the controllable oscillator; a coarse-tuner implemented in order to control the controller for controlling the oscillator using the second data pattern and a number of clock periods of the oscillator in order to reduce the oscillator clock frequency of the controllable oscillator or to increase the oscillator clock frequency; a fine-tuner operable after the coarse-tuner was operable and implemented in order to control the controller for controlling the oscillator using the first data pattern and a temporally subsequent first data pattern and a number of clock periods of the oscillator between the first data pattern and the temporally subsequent first data pattern in order to reduce the oscillator clock frequency of the controllable oscillator or to increase the oscillator clock frequency of the controllable oscillator, whereby the oscillator clock frequency is obtained with the relative second accuracy which is equal to the clock frequency underlying the data stream or equal to a multiple or a fraction of the clock frequency underlying the data stream, wherein the coarse-tuner and the fine-tuner are operable in order to set bits of the first digital/analog converter; and a frequency-tracker which is implemented in order to be operable after a coarse tuning by the coarse-tuner and after a fine tuning by the fine-tuner in order to set bits of the second digital/analog converter.