US 2008/0290939 A1 · Method and apparatus for distortion correction of RF amplifiers

Abstract

A method of reducing distortion in the output of an amplifier is provided. The method comprises subtractively combining baseband error signals with the appropriate phase shift with baseband input signals, the baseband error signals generated by subtractively combining delayed fed-forward portions of the baseband input signals with baseband converted portions of a fed-back amplified output signal, the amplified output signal being a distorted replica of combined up-converted baseband input signals. The baseband error signals being filtered prior to the combining function, and also providing inputs to a controller which adjusts active elements of the amplification and fed-back paths in order to minimize the distortion within the output of the amplifier.

Claims51

Dependent claims

A method comprising:

providing an amplifier for providing amplification of an applied RF input signal to generate an RF output signal;
generating a baseband error signal by combining a predetermined baseband portion of the RF output signal with a first predetermined baseband portion of a supplied RF input signal;
reducing distortion in the RF output signal by combining the baseband error signal with the supplied RF input signal;
and,
controlling an aspect of at least one of
the generation of the baseband error signal,
combining the baseband error signal with the applied RF input signal, and the amplifier
at least in dependence upon a magnitude of the baseband error signal.

5 more elements

A method comprising;

(a) amplifying a microwave signal with at least an amplifier to provide an output signal, the output signal being substantially an amplified replica of the microwave signal;
(b) providing two input signal components according to a predetermined coordinate system;
(c) combining predetermined portions of the two input signal components according to the predetermined coordinate system to provide the microwave signal;
(d) extracting a predetermined portion of the output signal;
(e) separating the predetermined portion of the output signal into two output signal components according to the coordinate system;
(f) combining each output signal component with a predetermined portion of its respective input signal component to provide an error signal component, thereby substantially suppressing the input signal component and substantially unaffecting distortion components of the output signal;
(g) combining each error signal component with its respective input signal component to provide suppression of the distortion in the output signal;
and,
(h) providing at least a control signal, the control signal being one of a plurality of control signals, each control signal for controlling an aspect of at least one of steps (a) through (g) and being determined in dependence upon a measure of the error signal components.

6 more elements

A circuit comprising:

an input port, the input port for receiving a RF signal;
an amplifier, the amplifier for providing amplification of an applied RF input signal electrically coupled to an input port of the amplifier and generating an RF output signal electrically coupled to an output port of the amplifier, the amplifier also comprising at least a control port for receiving a control signal, the control signal for adjusting an aspect of performance of the amplifier;
an error generator circuit, the error generator circuit having at least a first input port for receiving a predetermined baseband portion of the RF output signal, a second input port for receiving a first predetermined baseband portion of the supplied RF signal, a control port for receiving a control signal, the control signal controlling an aspect of the error generator circuit, and a baseband error port for providing a baseband error signal, the baseband error signal being generated in dependence upon at least the predetermined baseband portion of the supplied RF signal and predetermined baseband portion of the RF output signal;
a error combiner circuit, the error combiner circuit comprising at least a first combine port for receiving the baseband error signal, a second combine port for receiving the supplied RF signal, an output port electrically coupled to the input port of the amplifier for providing the RF input signal, RF signal being generated in dependence upon at least the baseband error signal and supplied RF signal, and a control port for receiving a control signal, the control signal for adjusting an aspect of performance of the error combiner circuit;
and,
a controller, the controller having at least a control port for providing controlling at least a control signal to at least one of the amplifier, error generator circuit, and error combiner circuit, the control signal generated at least in dependence upon a magnitude of the baseband error signal.

3 more elements

A circuit comprising:

(a) an amplifier, the amplifier having at least an input port, the input port receiving a microwave signal to be amplified, an output port, the output port providing the output signal, the output signal being substantially an amplified replica of the microwave signal, and a amplifier control port, the amplifier control port for receiving a control signal, the control signal for varying an aspect of the amplifier;
(b) two input ports, each input port for receiving an input signal component, each input signal being a predetermined portion of a transmit signal and according to a predetermined coordinate system;
(c) a combiner, the combiner having at least two input ports, each input port for receiving one of at least two source signals, an output port for providing a microwave signal, and a control port for receiving a control signal and adjusting an aspect of the combiner in dependence upon at least the control signal;
the combiner providing the microwave signal by combining predetermined portions of the two input signal components according to the predetermined coordinate system;
(d) a coupler, the coupler electrically coupled to the output of the amplifier and having at least an output port for providing a tap signal, the tap signal being a predetermined portion of the output signal;
(e) a separator, the separator having at least a tap port, for receiving the tap signal, two output ports, each output port providing an output signal component, each output signal component being a predetermined portion of the tap signal according to the coordinate system, and a separator control port, the separator control port for receiving a control signal adjusting an aspect of separator;
(f) a combiner circuit, the combiner circuit having at least two signal component ports, each signal component port for receiving an output signal component, two input ports, each input port for receiving a predetermined portion of an input signal, two output ports, each output port providing an error signal component, each error signal generated by combining a output signal component with its respective input signal component to provide an error signal component, each error signal component substantially suppressing the input signal component and substantially unaffecting distortion components of the output signal;
(g) a measurement circuit, the measurement circuit comprising at least a measurement port for providing a measurement signal, the measurement signal being generated in dependence upon at least a measure of one of the error signal components;
(h) an error combiner, the error combiner having at least two error ports, each error port for receiving an error signal component, two signal ports, each signal port for receiving an input signal component, and two output ports, each output port providing a source signal, the source signal being generated in dependence upon the error signal component and input signal component and essentially suppressing distortion in the output signal;
and,
(i) a controller, the controller comprising at least a receive port, the receive port for receiving the measurement signal, and at least a control output port, the control output port providing a control signal, the control signal being determined in dependence upon the measurement signal.

8 more elements

Dependencies are inferred from the claim text.

Method and apparatus for distortion correction of RF amplifiers

Life of this patent

Method and apparatus for distortion correction of RF amplifiers

Life of this patent

Abstract

Claims51