Patent ID: 8139676

Claim:
A wireless communication unit comprising: a frequency generation circuit; a phase shifter circuit operatively coupled to the frequency generation circuit; down-mixers operably coupled to the phase shifter circuit; a linearised transmitter operably coupled to the frequency generation circuit and having: a forward path for routing a signal to be transmitted; a feedback path, operably coupled to a power amplifier and the forward path for feeding back a portion of the signal to be transmitted, wherein the feedback path and forward path are operatively coupled to the frequency generation circuit and form two loops in quadrature, wherein the wireless communication unit is characterised in that the phase shifter circuit comprises independent phase shift elements arranged to receive two input quadrature signals (‘I’ and ‘Q’) generated by the frequency generation circuit and to independently phase shift the two input quadrature signals to produce and provide two quadrature output signals to the down-mixers.