Data-dependent jitter pre-emphasis for high-speed serial link transmitters

Abstract

In the context of high-speed serial links, data-dependent jitter compensation techniques performed using phase pre-distortion. Broadly contemplated is an expansion of the notion of pre-emphasis beyond conventional amplitude compensation of ISI, whereby phase pre-emphasis for compensating data-dependent jitter (DDJ) is introduced. DDJ can be addressed by exploiting the relationship between the data sequence and the timing deviation. Phase pre-emphasis improves the signal integrity with little additional power consumption in the transmitter and with no cross-talk penalty.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to data equalization techniques for high speed serial links. BACKGROUND OF THE INVENTION [0002] High bandwidth chip-to-chip interconnection is a crucial part of many systems today. High speed inputs / outputs (I / Os) are extensively used in server processors, memory-central processing unit (CPU) interfaces, multiprocessor systems, and gaming applications. With increasing speed of on-chip data processing, there is an increasing demand for higher data rates. These high speed I / Os must also be capable of supporting low cost package and board technologies which introduce large signal degradation through bandwidth loss, reflection, and crosstalk. [0003] Equalization of high-speed serial links has evolved to compensate inter-symbol interference (ISI) caused by frequency-dependent attenuation found in interconnects. Pre-emphasis-based equalization in the transmitter and decision feedback equalization in the receiver figure ...

AI Technical Summary

Benefits of technology

[0006] In accordance with at least one presently preferred embodiment of the invention, there is broadly contemplated an expansion of the notion of pre-emphasis beyond conventional amplitude compensation of ISI, whereby phase pre-emphasis for compensating data-dependent jitter (DDJ) is introduced. DDJ can be addressed by exploiting the relationship between the data sequence and the timing deviation. Phase pre-emphasis improves the signal integrity with little additional power consumption in the transmitter and with no cross-talk penalty.

Problems solved by technology

Currently, one challenge of equalization is minimizing power consumption while still improving signal integrity in the presence of attenuation and reflections.

The use of amplitude pre-emphasis techniques, such as feed forward equalization, increases the power consumption and chip area and places additional demands on the dynamic range of the transmitter.

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