Abstract: An optical routing network provides function-specific routing, in the optical domain, of radio frequency (RF) signals between inputs to the network and function-specific outputs from the network. RF signals input to the network may comprise signals received by elements of a multi-function array antenna for routing to function-specific receiving equipment or signals from function-specific transmitting equipment for routing to selected elements of the antenna for transmission. The optical routing path through the optical routing network is chosen by selecting one or more predetermined optical carrier wavelengths in the optical routing network, each carrier wavelength being associated with a particular function of the antenna.

Abstract: A tuneable filter is provided in which a received signal in a first frequency range is translated to a signal of a higher frequency range by a switchable frequency oscillator signal, filtered in a narrow band filter and then down-converted, possibly to the first frequency range. The switchable frequency oscillator signals are generated by a synthesizer which operates by mixing oscillator signals of different frequencies, selected by fast-switching microwave switches, in order to generate the required range of oscillator signal frequencies.