Patent ID: 8855585

Claim:
An apparatus comprising: an upconverter comprising at least one transistor; an analog predistorter configured to receive an input signal and to generate a predistorted signal that at least partially corrects non-linearity of the at least one transistor of the upconverter; and a filter disposed in a signal path between the predistorter and the upconverter, wherein the filter is configured to filter the predistorted signal to generate a filtered predistorted signal, wherein the filtered predistorted signal is provided as an input to the upconverter, wherein the filter is configured to reduce out-of-band noise generated by the predistorter, wherein the analog predistorter comprises: a resistor having first and second terminals, wherein the first terminal is electrically connected to a first node and the second terminal is coupled to a second node; a first bias current generator having an output electrically connected to the first node; a first operational amplifier having an inverting input connected to a first baseband input terminal, a non-inverting input electrically connected to the first node, and an output associated with a first input of the upconverter; a first transistor having a gate connected to the output of the first operational amplifier, a source connected to a voltage reference, and a drain connected to the first node; a second bias current generator having an output electrically connected to the second node; a second operational amplifier having an inverting input connected to a second baseband input terminal, a non-inverting input connected to the second node, and an output associated with a second input of the upconverter; and a second transistor having a gate connected to the output of the second operational amplifier, a source connected to the voltage reference, and a drain connected to the second node.