| 摘要 |
FIELD: physics; alarm systems. ^ SUBSTANCE: present invention pertains to the technique of transmitting monitoring and alarm signals from guarded objects, for example, transportation facilities to a centralised guarding station. Each of the messages from any guarded object is transmitted and received at the centralised guarding station in a strictly defined time interval. At the centralised guarding station, individual control signals are generated for each guarded object, and transmitted as a binary code on a radio channel as part of command messages. For transmission of command messages, time intervals are chosen, which do not intersect with the message reception time. Alarm events may occur at the guarded object, after detection of which the corresponding alarm messages are sent to the centralised guarding station. From the deciphered alarm signal at the centralised guarding station, the alarm event which occurred at the guarded object can be determined, and appropriate measures can be taken. To prevent false information generated for the centralised guarding station by intruders when they attack the guarded object, hopping-signal technology is used, where the binary code of each message from the guarded will be sent in a pseudorandom chosen time within a chosen interval and at an arbitrary carrier frequency within a frequency interval, permitted for the given system. The proposed method remains effective if there is need for generating in the centralised guarding station, commands for messages, sent at the same time, but at different carrier frequencies. Use of the technology increases the number of guarded objects, controlled by the same centralised guarding station, subject to active limitations of nominals of received radio frequencies and radiation power of transmitters. ^ EFFECT: increased the number of guarded objects, controlled by the same centralised guarding station, subject to active limitations of nominals of received radio frequencies and radiation power of transmitters. ^ 8 cl, 4 dwg |
