Telefonaktiebolaget Lm Ericsson (publ)

Jan-Christian Nystrom

Par S Bergsten

Goran Orneving

Mats Lennart Carlsson

A method and system for reducing spurious signal content in transmitters is described. A lowpass or bandpass filter can be inserted after an input signal node of a transmitter to remove interfering signals generated, for example, from another input signal node of the transmitter. In this way integration of the transmitter circuitry is enhanced.

Spurious signal reduction in RF transmitter integrated circuits

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.

Growing community of inventors

Sollentuna, Sweden

Jan-Christian Nystrom