Patent ID: 9225507
Filing Date: 2015-12-29
Classification: G04F,G06F,H03L,H03M,H04L

Abstract:
1. An apparatus for aligning a first local oscillator (LO) clock generated by a controllable LO clock generator in a first radio frequency (RF) path with a second LO clock in a second RF path, the apparatus comprising: a synchronization channel utilizing at least one of transmit buffers and receive buffers, the synchronization channel configured to exchange a synchronization clock between the first and second RF paths; a first phase detector configured to measure a phase alignment between the first and second LO clocks and to generate an output; a second phase detector configured to measure the phase alignment between the second and first LO clocks and to generate an output; and a loop filter configured to drive the controllable LO clock generator using the phase alignments, wherein: the first RF path includes the first phase detector, the second RF path includes the second phase detector, the outputs from the first and second phase detectors are subtracted at the input of the loop filter, a true phase relationship between the first and second LO clocks is determined, and systematic and environmental variability due to the at least one of transmit buffers and receive buffers is cancelled.