Agere Systems Inc.

Tomasz Thomas Prokop

Dominic Wing-Kin Yip

Christopher John Nicol

The span of a linear transversal equalizer filter moves according to the current positions of the multi-paths to a receiver. The alignment of the filter span is measured quantitatively with respect to the current positions of the multi-paths. Adjustments are made to the filter span to enable the linear transversal filter to capture most of the available energy of the transmitted signal. The low-pass-filtered magnitudes of tap weights of the linear filter are multiplied with values of a function which has zeroes at desired points for the larger tap weights, and a gradient of the function at its zeroes being non-zero. The magnitude of the alignment measurement signal is used as a quantitative measure of the alignment of the equalizer span, while the sign of the alignment measurement signal can be used to decide the direction that the span should be moved in.

Measurement of equalizer span alignment with respect to channel condition

A communications circuit can operate in a first mode, such as a diversity mode including space time transmit diversity (STTD). In this mode, a number of equalizer filter portions connected to a number of post-equalizer processors are employed. When the diversity mode is not required, the extra equalizer filter portions would represent a waste of power consumption and/or chip space. A combining circuit and suitable control circuitry are provided to allow use of the additional equalizer filter portions to be made in other operating modes. Appropriate trade-offs can be made based on power consumption and performance.

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Glenhaven, Australia

Tomasz Thomas Prokop