DEVICE FOR ALARMING ABOUT FLOOD OR MUDFLOW Russian patent published in 2000 - IPC

FIELD: equipment for warning population against natural disaster. SUBSTANCE: device uses phase-shift keyed signal, which is emitted by transmitter, received and selected by receiver, detected and used for turning on sound alarm. Type of sound alarm describes level of flood or mudflow, while detected code describes geographical coordinates of location of flood or mudflow. Transmitters are mounted in regions which are dangerous for flood or mudflow. Receiver is mounted at alarm station. Use of complex phase-shift keyed signal provides possibility to use novel selection type: structural selection, which provides increased stability to noise and reliability for detection of said signal among other signals and noises that operate in same bandwidth at same time. Suppression of false signals (noise) received via direct traffic channel at frequency W_dir and mirror channel at frequency W_m, uses phase-compensation method. Suppression of false signals (noise) received via combination channels at frequencies W_c1 and W_c2 uses narrow-band filtration method. EFFECT: increased stability to noise, prevention of ambiguous measurement of carrier frequency and other signal parameters due to suppression of false signals (noise) received via direct traffic, mirror and combination channels. 3 dwg