Warning method and apparatus and parallel correlator particularly useful therein

摘要: A method and apparatus for monitoring a particular location the occurrence of predetermined condition, such as fire, smoke, gas, etc., involves continuously transmitting, from transmitter located at monitored location, to receiver, source electrical signals repetition rate having period less than interval between by least one order magnitude, interrupting transmission upon sensing condition. For example, transmitted may be coded bursts pulses burst periods milliseconds or nanoseconds, spaced intervals seconds. Also, described is parallel correlator which used decoder.