A first sampling circuit takes phase offset first samples of a received serial data stream in response to a first edge of a sampling clock and a first comparator circuit determines whether the plurality of phase offset first samples have a same logic state. A second sampling circuit takes phase offset second samples of the received serial data stream in response to a second edge of the sampling clock, opposite the first edge, and a second comparator circuit determines whether the phase offset second samples have a same logic state. One of the first samples or one of the second samples is then selected in response to the determinations made by the first and second comparator circuits. A serial to parallel converter circuit generates an output word including the selected one of the first and second samples.

A circuit for performing clock recovery according to a received digital signal. The circuit includes at least an edge sampler and a data sampler for sampling the digital signal, and a clock signal supply circuit. The clock signal supply circuit provides edge clock and data clock signals offset in phase from one another to the respective clock inputs of the edge sampler and the data sampler. A digital phase detector determines if the data clock is early, late or synchronized with respect to data value transitions in the digital signal, and based on that determination provides a phase adjustment signal to the clock signal supply circuit, which is operable to vary phases of the data and edge clock signals accordingly.

A clock and data recovery apparatus is provided that includes a sampling circuit, a storage circuit and a determining circuit. The sampling circuit includes sampling units each sampling a received data according to one of reference clock signals to generate a sampling result. The storage circuit includes FIFO storage units configured to store the sampling result of the received data corresponding to different time spots. The determining circuit is configured to set a certain number of received data as a reference data pattern, to adjust a starting position of a sampling window according to a transition point of sampled values within the reference data pattern when only one data transition exists therein and adjust a length of the sampling window according to an amount of high state sample points of the sampled values within the reference data pattern when more than one data transitions exist therein.

A clock data recovery circuit including a phase blender, a phase detector, a data sampling position detector and a data selector is provided. The phase blender generates a third clock signal and a fourth clock signal according to a first clock signal and a second clock signal. The phase detector samples a data signal according to the first and second clock signals to generate first sampled data, second sampled data and a phase state signal. The data sampling position detector samples the data signal according to the third and fourth clock signals to generate third sampled data, fourth sampled data and a control signal. The data selector generates output data according to the control signal and the phase state signal.

Embodiments of this application disclose a phase detection method, a phase detection circuit, and a clock recovery apparatus. The method includes: receiving a first signal, and deciding a (2M1) level of the first signal to obtain a decision result, where the first signal is a (2M1)-level signal, and M is a positive integer: obtaining a response amplitude parameter of a transmission channel; extracting clock phase information in the first signal based on the first signal, the decision result, and the response amplitude parameter; and determining output clock phase information based on at least three decision results and at least three pieces of clock phase information in at least three symbol periods. According to the foregoing method, a stable phase detection gain can be achieved when a clock phase is tuned to a pulse response edge

A clock and data recovery apparatus is provided that includes a sampling circuit, a storage circuit and a determining circuit. The sampling circuit includes sampling units each sampling a received data according to one of reference clock signals to generate a sampling result. The storage circuit includes FIFO storage units configured to store the sampling result of the received data corresponding to different time spots. The determining circuit is configured to set a certain number of received data as a reference data pattern, to adjust a starting position of a sampling window according to a transition point of sampled values within the reference data pattern when only one data transition exists therein and adjust a length of the sampling window according to an amount of high state sample points of the sampled values within the reference data pattern when more than one data transitions exist therein.

A first sampling circuit takes phase offset first samples of a received serial data stream in response to a first edge of a sampling clock and a first comparator circuit determines whether the plurality of phase offset first samples have a same logic state. A second sampling circuit takes phase offset second samples of the received serial data stream in response to a second edge of the sampling clock, opposite the first edge, and a second comparator circuit determines whether the phase offset second samples have a same logic state. One of the first samples or one of the second samples is then selected in response to the determinations made by the first and second comparator circuits. A serial to parallel converter circuit generates an output word including the selected one of the first and second samples.

The present invention relates to a method for synchronizing digital data sent in series by a transmitter to a receiver, and to a device allowing such a method to be implemented. The invention aims to provide a method for synchronizing serial digital data without using a FIFO memory. The invented is based on the use of a single clock, in particular that of the receiver.

Method for synchronizing digital data sent in series by a transmitter having a clock frequency freq1 to a receiver having a clock frequency freq2, comprising the steps a) to d) iterated until a stoppage condition is met and a step e): a) sending a digital datum from the transmitter to the receiver; b) generating N channels, each ith channel containing the datum, and being time shifted with respect to the (i1)th channel, with N3 and 2<i<N; c) sampling the N channels at the frequency freq2; d) comparing the N channels in groups of (2m+1) successive channels, m1 and such that (2m+1)N, and selecting groups of (2m+1) channels in which the data of these channels are identical in each iteration; e) selecting a channel belonging to the selected groups, the data contained in this channel being considered to be synchronized and in phase with the receiver and defining a variable P equal to the value i of the selected channel.

A circuit for performing clock recovery according to a received digital signal. The circuit includes at least an edge sampler and a data sampler for sampling the digital signal, and a clock signal supply circuit. The clock signal supply circuit provides edge clock and data clock signals offset in phase from one another to the respective clock inputs of the edge sampler and the data sampler. A digital phase detector determines if the data clock is early, late or synchronized with respect to data value transitions in the digital signal, and based on that determination provides a phase adjustment signal to the clock signal supply circuit, which is operable to vary phases of the data and edge clock signals accordingly.