| 摘要 |
The transponder system according to the present invention presents a light weight portable or mobile system for localization of movable objects, e.g., for surveillance of valuable transpor ts and the like. The small unit constituting the transponder contains a receiver (I) of paging type, a decoder (2), a logic unit (3), a transmitter portion (10), a built-in antenna and power supply (11). Additionally the system is further controllable by means of an existin g tested radio system for paging. The advantages of utilizing an already existing paging system owes for one part to the fact th at functionality is well tested at the same time as a general covering range its obtained and further that costs for building up and operation of this are eliminated. Control information being sent to the transponder is comprising first a number of symbols defining a certain basic function for the built-in marker transmitter (10) while the remaining symbols further are constituting contro l code and control data for this specific fraction, consequently at least the frequency, transmit power and transmitting sequences of the marker transmitter are controllable.
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