Title: Programmable digital gain circuit and corresponding method
Application Number: 200610159931 Application Date: 2006.09.26
Publication Number: 1941757 Publication Date: 2007.04.04
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H04L25/03;H03G3/20
Applicant(s) Name: Altera Corp. Address:
Inventor(s) Name:
Attorney & Agent: zhaorong min xuefeng
Abstract:
    Equalization circuitry may be used to compensate for the attenuation of a data signal caused by a transmission medium. The control circuitry for the equalization circuitry may generate control inputs for equalization stages that control the amount of gain provided to the data signal. A comparator may determine whether the gain from the equalization circuitry is less than or more than the desired amount of gain. A programmable up/down counter may adjust the counter value based on the output of the comparator. The counter value may be converted into one or more analog voltages using one or more digital-to-analog converters. These analog voltages may be provided to the equalization stages as control inputs. The control circuitry may also include hysteresis circuitry that prevents the counter value from being adjusted when the gain produced by the equalization stages is close to the desired amount of gain.
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