Patent ID: 10142090

Abstract:
Octagonal phase rotator apparatus is provided for producing an output signal that is phase dependent on a digital control code. The apparatus includes an I-mixer, a Q-mixer, and first and second IQ-mixers. The I-mixer is responsive to I-control bits of the digital control code. The Q-mixer is responsive to Q-control bits of the digital control code. The first and second IQ-mixers are respectively responsive to one or more IQ1-control bits and one or more IQ2-control bits of the digital control code. The I-mixer comprises an I-DAC for steering current between a positive phase IP and a negative phase IN of an in-phase (I) signal wherein the one or more I-control bits control switching of a first current unit between IP and IN, and a set of amplifiers for weighting the phases IP and IN, in dependence on current steered to each phase by the I-DAC, to produce a weighted I-signal.