The broadband microwave frequency shifter is an electro-optical device that accomplishes frequency shifting, or translation by the use of serrodyning or mixing techniques. A first optical signal is modulated with the radio frequency signal desired to be translated and processed to produce an upconverted...http://www.google.com/patents/US6043926?utm_source=gb-gplus-sharePatent US6043926 - Electro-optical broadband microwave frequency shifter
