Abstract: A system is provided for passively producing at least two distinct signal patterns. The system can be used for passively identifying friend or foe in an environment and operates in a hyper spectral mode that accommodates multiple bands simultaneously. Exemplary embodiments receive radiated energy within a resonant cavity, and use an absorber and a reflector to absorb and reflect desired frequencies of the incoming energy. A controller is connected to the IFF system and controls the switching back and forth between the absorber and the reflector to produce a signal having a desired data format. The encoded data can be used to determine the status of the candidate target.

Abstract: A method and apparatus is described for signal processing to identify an object in an environment. A precursor associated with an electromagnetic wave interacting with the object is received and a property of the object identified using precursor characteristics. The electromagnetic wave is transmitted with a characteristic including a pulse having a sharp rise time so as to generate the precursor. The pulse is generated using a circuit including capacitive discharge and a semiconductor device such as a Drift Step Recovery Diode. Alternatively the pulse may be generated using a microwave diode switch and a broadband semiconductor amplifier or a traveling wave tube amplifier. The characteristic may also includes a signal with a phase reversal generated by dividing the electromagnetic signal and phase modulating the first electromagnetic signal with the divided signal to generate the phase reversal so as to generate the precursor.