Telefonaktiebolaget Lm Ericsson (Publ)

Par S Bergsten

Bo Gosta Hedberg

Mark Anthony Briffa

Jan-Christian Nystrom

A predistortion signal is generated which compensates for third order and higher order intermodulation distortion over a wideband. The predistortion signal is applied to an input radio frequency signal, for example a multi-tone radio frequency signal. The predistortion signal is a low order polynomial having adjustable coefficients. The predistortion signal can compensate for intermodulation products produced a nonlinear amplifier, and the polynomial coefficients can be adjusted based on the difference between the amplifier output and the input radio frequency signal.

Method and apparatus for wideband predistortion linearization

A system for transmission of combined, multi-carrier signals wherein combiner/filters, commonly called combiners, have been eliminated. A cartesian feedback loop linearizes the system and thereby suppresses carrier frequency intermodulation by feeding back a portion of the combined multi-carrier signal to each channel device.

Cartesian multicarrier feedback

An apparatus for compensating the phase rotation in the feedback loop of a cartesian feedback power amplifier in a final transmitter stage for quadrature modulation of the complex difference signal between a complex input signal and the corresponding complex feedback signal with a complex modulation signal for forming a modulated real valued first signal and for quadrature modulation of the output signal from the power amplifier with a complex demodulation signal for forming the complex feedback signal. The phase shift between the first signal and the second signal and between the quadrature component of the first signal and the second signal is detected for determining the phase rotation of the feedback loop. Furthermore, the phase rotation of the complex modulation signal can be changed with a compensating phase rotation defined by the determined phase rotation.

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Solna, Sweden

Par S Bergsten