Rambus Inc.

Other

Jason C Wei

Jared L Zerbe

Mark A Horowitz

Vladimir Marko Stojanovic

Bruno Werner Garlepp

Anthony G Bessios

Grace Tsang

Andrew C C Ho

Andrew P Ho

Kevin S Donnelly

Yohan Usthavia Frans

Nhat M Nguyen

Todd W Bystrom

Dennis Kim

Benedict C Lau

Kun-Yung Chang

Donald Victor Perino

Tsyr-Chyang Ho

Yiu-Fai Chan

Samir A Patel

Kun-Yung K Chang

Marc A Horowitz

A signaling system is described. The signaling system comprises a transmit device, a receive device including a partial response receive circuit, and a signaling path coupling the transmit device and the receive device. The receive device observes an equalized signal from the signaling path, and includes circuitry to use feedback from the most recent previously resolved symbol to sample a currently incoming symbol. The transmit device equalizes transmit data to transmit the equalized signal, by applying weighting based on one or more data values not associated with the most recent previously resolved symbol value.

Partial response receiver

Equalizing receiver

A circuit, such as a CDR circuit, includes a sampler to receive a data signal having a variable data bit-rate responsive to a clock signal in an embodiment of the present invention. A clock circuit is coupled to the sampler and generates the clock signal responsive to a selectable update rate and a selectable phase adjust step-size. In a second embodiment of the present invention, the clock circuit includes a Stall logic that is coupled to first, second and third stages and is capable to hold the phase adjust signal responsive to the first and second stage output signals. In a third embodiment of the present invention, an indicator detects the variable data bit-rate and a counter provides the selectable phase adjust step-size for the adjust signal. In a fourth embodiment of the present invention, the clock circuit includes the Stall logic, the indicator and the counter. In a fifth embodiment of the present invention, the clock circuit includes an Averaging circuit to output a phase adjust signal responsive to the averaging of a first and second adjust signals for a predetermined period of time.

Clock-data recovery ('CDR') circuit, apparatus and method for variable frequency data

A receive circuit for receiving a signal transmitted via an electric signal conductor. A first sampling circuit generates a first sample value that indicates whether the signal exceeds a first threshold level, and a second sampling circuit generates a second sample value that indicates whether the signal exceeds a second threshold level. A first select circuit receives the first and second sample values from the first and second sampling circuits and selects, according to a previously generated sample value, either the first sample value or the second sample value to be output as a selected sample value.

An integrated circuit device having a receive circuit is disclosed. The receive circuit generates first and second sets of samples of incoming symbols during first and second time intervals, respectively. A select circuit selects, based at least in part on the first set of samples, at least one sample from the second set to be output as a received data value. The integrated circuit device further includes a transmit circuit to generate an output symbol during a third time interval. The output symbol has an amplitude based, at least in part, on a transmit data value for which an output symbol was generated during a time interval prior to the third time interval.

A circuit, such as a CDR circuit, includes a sampler to receive a data signal having a variable data bit-rate responsive to a clock signal in an embodiment of the present invention. A clock circuit is coupled to the sampler and generates the clock signal responsive to a selectable update rate and a selectable phase adjust step-size. In a second embodiment of the present invention, the circuit includes a Stall logic that is coupled to first, second and third stages and is capable to hold the phase adjust signal responsive to the first and second stage output signals. In a third embodiment of the present invention, an indicator detects the variable data bit-rate and a counter provides the selectable phase adjust step-size for the adjust signal. In a fourth embodiment of the present invention, the circuit includes the Stall logic, the indicator and the counter. In a fifth embodiment of the present invention, the circuit includes an Averaging circuit to output a phase adjust signal responsive to the averaging of a first and second adjust signals for a predetermined period of time.

A clock recovery circuit samples an incoming data stream that includes sequences of signal transitions. A transition detector categorizes the received signal transitions into various types, such as those associated with 2PAM and 4PAM signaling schemes. Select logic control circuitry analyzes the signal-transition types to determine which of the transition types is best suited for clock recovery. This determination relies upon a number of factors, including for example whether the received signal is a 4PAM signal or a 2PAM signal, the existence of a pattern within the received data, or the relative abundance or scarcity of certain types of transitions.

System and method for selecting optimal data transition types for clock and data recovery

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Cupertino, CA, United States of America

Jason C Wei