Abstract: A method for extracting a number of temporal frequencies occurring in a fire and false fire condition concurrently from two or more radiation detectors for receiving signals, a correlation detector for each frequency and sensor, and a storage buffer for the temporal frequencies extracted and sensors employed, so as to distinguish a small fire signal in the presence of a much larger false fire signal whether random in nature or not. The ratio of each extracted frequency following proper qualification is compared to the ratio band for fire and an output signal is generated when the ratio at one or more temporal frequencies indicates a fire.