Agere Systems Inc.

Anadigics, Inc.

Shaorui Li

Lawrence Allen Rigge

Jinghong Chen

John Thomas Bayruns

A passive mixer includes a transconductance amplifier having a source degeneration capacitance. The transconductance amplifier has an input for receiving an input signal and an output for outputting a current signal. A multiplier is provided for mixing a local oscillator signal with the current signal so as to provide an output signal at an output of the passive mixer. A capacitive load is connected to the output of the passive mixer.

Passive mixer having transconductance amplifier with source degeneration capacitance

The invention provides a system for providing tunable balanced loss compensation in an electronic filter. Tunable balanced loss compensation is provided by using cross-connected balanced transconductors and self-connected balanced transconductors. The cross-connected balanced transconductors and the self-connected transconductors compensate the unbalanced loss across the electronic filter. The self-connected balanced transconductors compensate the balanced loss across the electronic filter. Further, the cross-connected and the self-connected balanced transconductors are tunable by adjusting the values of their transconductances, thereby providing tunable balanced loss compensation.

Tunable balanced loss compensation in an electronic filter

In one embodiment, an amplifier circuit has at least one branch and current-source circuitry providing a tail current to the branch, which has at least one load tank, at least one input transistor coupled to the load tank, and variable-impedance circuitry coupled between an input node of the amplifier circuit and the gate of the input transistor. The transconductance of the input transistor can be altered to achieve two or more different gain settings for the amplifier circuit. The variable-impedance circuitry can be controlled to contribute any one of at least two different levels of impedance to the overall input impedance of the amplifier circuit. If the transconductance of the input transistor is reduced, then the variable-impedance circuitry can increase the level of impedance contributed to the overall input impedance of the amplifier circuit such that the overall input impedance of the amplifier circuit remains substantially unchanged.

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Summit, NJ, United States of America

Shaorui Li