IMPROVED METHOD AND APPARATUS FOR UP-CONVERSION OF RADIO FREQUENCY (RF) SIGNALS

摘要

This patent describes a method and system which overcomes the LO-leakage problem of direct conversion and similar RF transmitters. To solve this problem a virtual LOTM signal is generated within the baseband which is tune d to the incoming RF signal. The virtual local oscillator (VLO) signal is constructed using signals that do not contain a significant amount of power (or no power at all) at the wanted output RF frequency. Any errors in generating the virtual LO signal are minimized using a closed loop correctio n scheme.