A Two-Tone Test Method for Continuous-Time Adaptive Equalizers

Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 51)


With the increasing demand of higher bandwidth, the data rate of I/Os is approaching the tens of gigahertz range. While the continuing advancement of process technology enables an I/O chip to run at such frequencies, the bandwidth of the communication channels, including cables and legacy backplanes, has become the limiting factor.

The bandwidth limitation of the channel causes ISI. Various equalization techniques, which multiply the inverse response of the channel to flatten out the overall frequency response, have been developed to compensate for this channel effect. In addition, the channel characteristics may not be known in advance and might be time-variant [59]. To cope with such problems, several adaptation algorithms have also been developed to adjust the overall system response depending on the channel conditions.

The equalizer can be implemented either in the transmitter or in the receiver. The implementation of the transmitter equalizer is relatively easier than that of the receiver equalizer because the required Finite Impulse Response (FIR) filter deals with the digital data at the transmitter side, rather than the received analog data at the receiver side [60, 61]. However, since channel information is not easily available at the transmitter, it is difficult to apply the adaptive technique at the transmitter.


Receive Analog Data Filter Deals Gigahertz Range Equalization Filter Adaptive Loop 
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© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Broadcom CorporationIrvineUSA
  2. 2.Santa Barbara College of Engineering Dept. Electrical & Computer EngineeringUniversity of CaliforniaSanta BarbaraUSA

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