WIRELESS COMMUNICATION UNIT, MODULATION CIRCUIT AND METHOD FOR FREQUENCY-DEPENDENT ADJUSTMENT THEREOF

A communication unit (300, 400, 500) is described that includes at least one antenna (302, 402, 502); a plurality of radio frequency (RF) circuits (304, 310, 404, 410) respectively coupled to at least one antenna (302, 402, 502); at least one sigma-delta modulator (316, 416, 616, 816) comprising a number of stages, each stage comprising at least one signal-feedforward coefficient (603, 604, 605), a filter and a feedback gain element, the at least one sigma-delta modulator (316, 416, 616, 816) coupled to the plurality of RF circuits (304, 310, 404, 410) and configured to perform sigma-delta modulation; and a controller (340, 440, 640, 840) operably coupled to the at least one sigma-delta modulator (316, 416, 616, 816). The at least one sigma-delta modulator (316, 416, 616, 816) comprises an input (315, 415, 602, 801, 802, 902) configured to receive multiple multi-phase input signals and the controller (340, 440, 640, 840) is configured to adjust the at least one signal-feedforward coefficient (603, 604, 605) of the at least one sigma-delta modulator (316, 416, 616, 816) when combining the multiple multi-phase input signals.