US 6,125,266 A · Dual band architectures for mobile stations having transmitter linearization feedback

Abstract

This invention teaches methods and apparatus for providing a low cost, low complexity, and low component count transmitter feedback function for use in mobile station transmitter linearization and self-test operations. Disclosed is a method for operating a mobile station of a type that includes a transmit chain having an output coupled to an antenna and a receive chain having an input coupled to the same or a different antenna. The method includes steps of: during a transmission time, (a) sampling an amplified signal prior to the amplified signal being applied to the antenna for transmission from the transmit chain; (b) downconverting a frequency of the sampled amplified signal to a lower frequency signal using a receive chain local oscillator signal normally used for downconverting a received signal to the first IF; and (c) demodulating the lower frequency signal to a baseband signal with a receive chain demodulator by using a second local oscillator signal that is normally used as a transmit chain modulator injection frequency signal. A further step of the method determines from the baseband signal an amount of predistortion of an input signal to the transmit chain in order to obtain a desired amount of linearization of the amplified signal.

Claims16

Dependent claims

A mobile station for conducting bidirectional wireless communications, comprising:

a transmit chain including a modulator, an upconverter for converting an output of the modulator to a transmit frequency signal, and a transmit amplifier having an input coupled to an output of the upconverter for amplifying said transmit frequency signal;
a receive chain including a receiver, a downconverter for converting an output of the receiver to an intermediate frequency (IF) signal, and a demodulator having an input coupled to an output of the downconverter;
circuitry for downconverting an output of said transmit amplifier to said IF signal and for selectively coupling said transmit amplifier downconverted signal to said input of said demodulator;
and
circuitry coupled to an output of said demodulator for determining an amount of predistortion to be applied to signals input to said modulator to achieve a desired amount of transmit frequency signal linearization.

2 more elements

Dependencies are inferred from the claim text.

Dual band architectures for mobile stations having transmitter linearization feedback

Life of this patent

Dual band architectures for mobile stations having transmitter linearization feedback

Life of this patent

Abstract

Claims16