US 6,054,896 A · Controller and associated methods for a linc linear power amplifier

Abstract

A LINC amplifier of a radio frequency transmitter provides substantially linear amplification from two nonlinear amplifiers by decomposing the original signal into two constant amplitude envelope, phase varying signals, which, when combined, constructively and destructively interfere to re-form the original signal. The output of the LINC amplifier, which is to be transmitted via an antenna, is an amplified form of the original signal. The LINC amplifier uses a digital control mechanism to control and adapt a digital compensation network that directly compensates for the imperfections of the analog RF environment, including the amplifiers. The mechanism monitors the combined amplifier output and adjusts the signal components in order to precisely compensate for any differences in the characteristics of the separate signal paths which would cause the combination not to accurately represent the original signal. The mechanism also corrects the component signals using information which can be applied to the amplifiers independent of the signal to be transmitted.

Claims20

Dependent claims

In a transmitter in which an input transmission signal is separated into multiple component signals that are processed along respective amplification chains and then combined to form an output transmission signal, and in which the amplification chains include compensation processors which modify the component signals based on sets of compensation parameters to compensate for differences in analog components of the amplification chains, a controller, comprising:

an adaptive compensation estimator which adaptively generates and updates the compensation parameters based on observations of signals within the transmitter;
and
a state machine which monitors a level of balance between the amplification chains and controls an operational mode of the transmitter, the state machine implementing at least the following states:
(a) a first state in which training signals are generated and applied to the amplification chains while substantially inhibiting emissions from an antenna, and in which the adaptive compensation estimator uses the training signals to adaptively update the compensation parameters, and
(b) a second state in which an input transmission signal is processed along the amplification chains to generate an output transmission signal, and in which the adaptive compensation estimator uses the input transmission signal to update the compensation parameters during transmission events to maintain the amplification chains in balance.

2 more elements

In an amplifier in which an input transmission signal is separated into multiple component signals that are amplified along respective amplification chains and then combined to form an output transmission signal, and in which the amplification chains include compensation processors which modify the component signals based on sets of compensation parameters to compensate for differences in analog components of the amplification chains, and in which an adaptive compensation estimator adaptively generates and updates the compensation parameters based on observations of signals within the amplifier, a method of controlling the amplifier, comprising:

placing the amplifier in a first state in which training signals are generated and applied to the amplification chains while the adaptive compensation estimator adaptively updates the compensation parameters;
monitoring a level of imbalance in the amplification chains while the amplifier is in the first state to determine whether the amplification chains are sufficiently balanced to commence transmissions;
and
when the amplification chains are sufficiently balanced to commence transmissions and a transmission event is pending, placing the amplifier in a second state in which an input transmission signal is separated and processed along the amplification chains to form an output transmission signal, and in which the adaptive compensation estimator uses the input transmission signal to adaptively update the compensation parameters during the transmission event.

1 more element

Dependencies are inferred from the claim text.

Controller and associated methods for a linc linear power amplifier

Life of this patent

Controller and associated methods for a linc linear power amplifier

Life of this patent

Abstract

Claims20