Abstract: A tracking loop of an interpolator based receiver includes clock elements that generate a plurality of clocks to sample a signal from a remote transmitter. The tracking loop includes samplers and voter elements that sample the signal with the clocks and generate samples that comparatively indicate a phase relationship between the signal and the clocks. Based on the comparison of the samples in the samplers and voter elements, the tracking loop either sends phase-shift signals to the clock elements to shift the phase of the clocks to match the phase of the signal, or sends a phase-flip signal to the clock elements to flip the clocks if the phase relationship between the signal and the clocks is about 180°. Once a phase match between the clocks and the signal is established, the tracking loop remains phase locked with the signal and provides a recovered signal.

Abstract: A receiving device within a digital electronic system includes a sampling unit, a voter block, and a local clock phase adjustment unit. The sampling unit samples an input line at three points in time at intervals of one half of a bit period. The sampling unit delivers the values obtained in the sampling process to the voter block. The voter block determines whether to deliver an up or a down vote to the local clock phase adjustment unit. The voter block communicates with the local clock phase adjustment unit via up and down control signals. The local clock phase adjustment unit determines whether the local clock phase should be adjusted, and if so, whether to advance or delay the local clock phase. If certain meta-stable conditions are observed by the voter block, the voter block will vote in one direction in order to push the system out of the meta-stable condition.

Abstract: Conventional receiver architectures are based on either frequency/phase tracking or oversampling. Both receiver types typically employ sensitive analog circuits, which create noise, consume power and utilize valuable space in their implementation. The invention adopts a novel approach to phase/frequency tracking that utilizes the edges or zero crossings of the input data waveform to effectively track the remote transmitter clock phase/frequency. This methodology minimizes the use of analog circuitry, thereby reducing the noise domain and the substrate space required for implementation of a tracking device.

Abstract: A method and system for improved phase tracking in communication systems is disclosed. In one embodiment, a method, comprises identifying a slow-time varying phase drift on a link by counting long term beats; calibrating an interpolator with the phase drift; predicting a future phase drift; and updating the interpolator periodically with the future phase drift prediction.

Abstract: Conventional receiver architectures are based on either frequency/phase tracking or oversampling. Both receiver types typically employ sensitive analog circuits, which create noise, consume power and utilize valuable space in their implementation. The invention adopts a novel approach to phase/frequency tracking that utilizes the edges or zero crossings of the input data waveform to effectively track the remote transmitter clock phase/frequency. This methodology minimizes the use of analog circuitry, thereby reducing the noise domain and the substrate space required for implementation of a tracking device.

Abstract: When signaling over cables or other media having significant return impedance, it is generally more efficient to use two conductors to carry two simultaneous bi-directional signals differentially, rather than utilizing unidirectional communications. Bi-directional communications increases the aggregate bandwidth of a pair of conductors. A conversion circuit converts unidirectional signaling between an edge-based receiver and a transmitter to simultaneous differential bi-directional signaling. A receiver for receiving data includes an edge processor operative to make decisions using edges of a received data stream and a communication circuit coupled to the edge processor. The communication circuit is operative to convert communications with the edge processor from a first format, such as unidirectional signaling, to a second format, such as differential bi-directional signaling.

Abstract: A tracking loop of an interpolator based receiver includes clock elements that generate a plurality of clocks to sample a signal from a remote transmitter. The tracking loop includes samplers and voter elements that sample the signal with the clocks and generate samples that comparatively indicate a phase relationship between the signal and the clocks. Based on the comparison of the samples in the samplers and voter elements, the tracking loop either sends phase-shift signals to the clock elements to shift the phase of the clocks to match the phase of the signal, or sends a phase-flip signal to the clock elements to flip the clocks if the phase relationship between the signal and the clocks is about 180°. Once a phase match between the clocks and the signal is established, the tracking loop remains phase locked with the signal and provides a recovered signal.

Abstract: A phase interpolator interpolates between a plurality of clock phases using a plurality of switching legs coupled to a common output. Each switching leg includes a pair of differential switching transistors each having a gate and two additional terminals, one of which is coupled to said common output. The gates are coupled to respective ones of the plurality of clock phases and their complements. Tails couple the other terminals of said switching transistors to ground. Each tail made up of a plurality of transistors. A load coupling the common output to a voltage.

Abstract: A method of recovering data from a modulated data signal includes tracking a transmitted clock with a plurality of locally-generated clock phases, estimating an average phase of previously detected edges, registering a pulse edge in the received stream of data at a transition phase corresponding to one of the plurality of locally-generated clock phases, determining whether a first symbol was received multiple times consecutively prior to the registered pulse edge, and using the determination of whether the first symbol was received multiple times consecutively in a receiver decision process.

Abstract: Conventional receiver architectures are based on either frequency/phase tracking or oversampling. Both receiver types typically employ sensitive analog circuits, which create noise, consume power and utilize valuable space in their implementation. The invention adopts a novel approach to phase/frequency tracking that utilizes the edges or zero crossings of the input data waveform to effectively track the remote transmitter clock phase/frequency. This methodology minimizes the use of analog circuitry, thereby reducing the noise domain and the substrate space required for implementation of a tracking device.

Abstract: A tracking data receiver which can compensate for deterministic jitter is disclosed. The device utilizes a history of past data received to determine which of multiple samples taken within a bit period to utilize. Due to deterministic jitter that can occur in data signal communication, the delay of waveform development varies with the ratio of 0's to 1's transmitted prior to the bit period being observed. The present invention exploits the predictable nature of the deterministic jitter to decide which sample to choose.

Abstract: A receiving device within a digital electronic system includes a sampling unit, a voter block, and a local clock phase adjustment unit. The sampling unit samples an input line at three points in time at intervals of one half of a bit period. The sampling unit delivers the values obtained in the sampling process to the voter block. The voter block determines whether to deliver an up or a down vote to the local clock phase adjustment unit. The voter block communicates with the local clock phase adjustment unit via up and down control signals. The local clock phase adjustment unit determines whether the local clock phase should be adjusted, and if so, whether to advance or delay the local clock phase. If certain meta-stable conditions are observed by the voter block, the voter block will vote in one direction in order to push the system out of the meta-stable condition.

Abstract: A receiver circuit is provided with a front amplifier to receive data from an I/O link driven by a remote clock signal; an interpolator to generate a local clock signal to track the remote clock signal encoded in the data; and a tracking mechanism to extract phase information about the remote clock signal from the data and to dynamically adjust the phase of the local clock signal that tracks the remote clock signal in accordance with extracted phase information for subsequent data processing functions, wherein the tracking mechanism is configured to predict the direction of a phase drift, and force the interpolator to move against the phase drift so as to reduce lock time.

Abstract: A tracking data receiver which can compensate for deterministic jitter is disclosed. The device utilizes a history of past data received to determine which of multiple samples taken within a bit period to utilize. Due to deterministic jitter that can occur in data signal communication, the delay of waveform development varies with the ratio of 0's to 1's transmitted prior to the bit period being observed. The present invention exploits the predictable nature of the deterministic jitter to decide which sample to choose.

Abstract: A method and system for improved phase tracking in communication systems is disclosed. In one embodiment, a method, comprises identifying a slow-time varying phase drift on a link by counting long term beats; calibrating an interpolator with the phase drift; predicting a future phase drift; and updating the interpolator periodically with the future phase drift prediction.

Abstract: A method and apparatus for asynchronously receiving a stream of data. The method and apparatus operate to detect edges within the stream of data and track a transmitted clock using multiple locally-generated clock phases. Moreover, the method and apparatus determine whether each edge arrives early or late relative to an expected arrival time and use the determination whether an edge arrived early or late in a receiver decision process. An exemplary embodiment of the apparatus to recover a clock from a stream of data includes an edge buffer, an edge processor, a multi-phase clock and an elastic buffer. The edge buffer receives the data stream and outputs an edge signal that indicates detection of an edge within the data stream. The edge processor is coupled to the edge buffer, determines an average phase of the detected edges and outputs a data signal and the average phase.

Abstract: A phase interpolator interpolates between a plurality of clock phases using a plurality of switching legs coupled to a common output. Each switching leg includes a pair of differential switching transistors each having a gate and two additional terminals, one of which is coupled to said common output. The gates are coupled to respective ones of the plurality of clock phases and their complements. Tails couple the other terminals of said switching transistors to ground. Each tail made up of a plurality of transistors. A load coupling the common output to a voltage.