US 6,321,072 B1Granted

Distortion control feedback loop utilizing a non-linear transfer function generator to compensate for non-linearities in a transmitter circuit

AssigneeConexant Systems, Inc.

InventorsStefano Cipriani, Lorenzo Carpineto, Anthony A. Takeshian

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Abstract

A transfer function generator provides the ability to provide a non-linear response in a feedback loop to compensate for non-linearities introduced elsewhere in the system. The transfer function generator includes a non-linear function generator configured to provide an output current that is a non-linear function of an input signal representing an error to be corrected. The transfer function generator can also include a linear function generator configure to provide a linear output current as a function of an input current representing the error corrected. Tuning devices can be provided to adjust the turn-on level of the non-linear function generator and the output level of the linear function generator to allow the transfer function generator flexibility in implementation.

Claims8

Dependent claims

A wireless communication device, comprising:

a power amplifier configured to amplify a signal for transmission by an antenna over a communications channel;
a power level sensor configured to sense the power level radiated from the antenna;
a comparator configured to compare the power level sensed by said power level sensor and a desired output power level and to provide an output indicating the difference between the two;
an integrator configured to integrate the output from said comparator to provide an output indicating an error level;
and
a transfer function generator, comprising:
a non-linear function generator configured to provide an output that is a non-linear function of an input representing the output from said integrator,
a linear function generator configured to provide a linear output as a function of an input representing the output from said integrator,
a junction configured to combine said non-linear output with said linear output;
a first tuning device to control turning on said non-linear function generator;
and
a second tuning device to control the output of said linear function generator;
wherein said transfer function generator is configured to provide a non-linear response to the error signal generated by the integrator to compensate for non-linearity introduced elsewhere in the communication device.

10 more elements

A wireless communication device, comprising:

a power amplifier configured to amplify a signal for transmission by an antenna over a communications channel;
a power level sensor configured to sense the power level radiated from the antenna;
a comparator configured to compare the power level sensed by said power level sensor and a desired output power level and to provide an output indicating the difference between the two;
an integrator configured to integrate the output from said comparator to provide an output indicating an error level;
a transfer function generator, comprising:
a non-linear function generator configured to provide, when said power amplifier is in its non-linear region, an output that is a non-linear function of an input representing the output from said integrator;
a linear function generator configured to provide, when said power amplifier is in its linear region, a linear output as a function of an input representing the voltage output from said integrator;
and
a junction configured to combine said non-linear output with said linear output;
a first tuning device to control the amount of input needed to turn on said non-linear function generator;
and
a second tuning device to control the output level of said linear function generator;
and
wherein said transfer function generator is configured to provide a non-linear response to the error signal generated by the integrator to compensate for non-linearity introduced elsewhere in the communication device.

11 more elements

Dependencies are inferred from the claim text.