COMMUNICATION UNIT AND METHOD FOR FREQUENCY SYNCHRONISING IN A CELLULAR COMMUNICATION NETWORK

摘要

A communication unit is capable of communicating in a wireless communication network. The communication unit (200) comprises a receiver for receiving timing signals from a plurality of serving wireless communication units (224, 250); a frequency synchronising circuit operably coupled to the receiver for synchronising an operating frequency of the communication unit (200) to a serving wireless communication unit (224) of the plurality of serving wireless communication units (224, 250); a quadrature coupled recursive software digital oscillator (330); and control logic (326) capable of controlling the frequency synchronising circuit to adjust an operating frequency of the communication unit. The frequency synchronising circuit comprises automatic gain control logic operably coupled to the quadraturecoupled recursive software digital oscillator (330) in parallel and arranged to scale the outputsof the quadrature coupled recursive software digital oscillator, intermittently. In this manner, a software digital oscillator may be practically realisable.