A method and system is described wherein a signal with a lower frequency is up-converted to a higher frequency. In one embodiment, the higher frequency signal is used as a stable frequency and phase reference. In another embodiment, the invention is used as a transmitter. The up-conversion is accomplished...http://www.google.com.hk/patents/US20090318097?utm_source=gb-gplus-share專利 US20090318097 - Method and System for Frequency Up-Conversion
