Telefonaktiebolaget Lm Ericsson (Publ)

Mark Anthony Briffa

Scott Leyonhjelm

Par S Bergsten

According to the invention, a Cartesian control means ( ) comprising a phase rotator ( ) and a phase adjuster ( ) is provided. With a method and a device according to the invention, a system is provided that is unconditionally stable with respect to non-phase alignment, regardless of input power changes, temperature and component ageing. No certain conditions need to be placed upon the control system to ensure stability, i.e. the system is non-obtrusive and requires no off-line calibration. The inclusion of the phase rotator ( ) and phase adjustment techniques into the Cartesian control system makes this possible.

Method and device in a telecommunication system

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.

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Lotsjovagen, Sweden

Mark Anthony Briffa