Abstract: The present invention is a system for the detection of chemical vapors in the atmosphere based on detecting radiation from the molecules of the vapor. The radiation is induced by energy transmitted from the system at a frequency close to an absorption frequency of the molecules of the vapor to be detected. The system provides a easily used means for the excitation and detection of the vapor by virtue of the common tuning control of the system and the direct detection of radiation at the absorption frequency excited by the transmitted energy.

Abstract: A radar target pattern recognizer which extracts a predetermined frequency range from a radar signal representation. A spectrum analysis is performed on the signal and then displayed relative to a logarithmic frequency scale with a subsequent comparison of the output with known target patterns.

Abstract: An ultrasonic whistle is mounted together with a pin on a window or door so that movement of the window or door causes relative movement between the whistle and pin. Such movement releases compressed gas from a container which activates the whistle. A central monitor in the building detects the output of the whistle and provides an output to activate alerting devices.