Apparatus and method for low voltage radio transmission

摘要

Apparatus and methods are disclosed related to low-voltage radio transmitters with high spectral purity. One such apparatus includes a baseband path with a predistortion stage, a programmable filter, and an upconverter core. In an embodiment, the programmable filter is placed between the predistortion stage and the upconverter core. In an embodiment, the programmable filter is configured by a controller to reject out-of-band noise introduced at the predistortion stage or earlier.

主权项

1. 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; anda 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.