Abstract: A method and device for increasing security with respect to transmission faults in an information-transmission system, particularly for the railroad field, in which an interrogation device and a passive response device are movable relative to one another, and the interrogation device transmits an interrogation signal, which can be periodically swept through a predetermined frequency band, preferably in the microwave range, and which during a read operation, receives during several periods from the passive response device, a frequency-selectively reflected interrogation signal, in accordance with a k-digit information item to be transmitted, which signal forms the response signal, with the response signals being suitably identified and one of a series thereof, preferably that with the least errors therein, being suitably through-connected for subsequent utilization, in which not only is the response signal with the fewest errors utilized, but of the signals having the same minimum number of errors, that respon

Abstract: A device for increasing security with respect to transmission faults in an information transmission system, particularly for the railroad field, in which an interrogation device and a passive response device are movable relative to one another, and the interrogation device transmits an interrogation signal, which can be periodically swept through a predetermined frequency band, preferably in the microwave range, and which during a read operation, receives during several periods from the passive response device, a frequency-selectively reflected interrogation signal, in accordance with a k-digit information item to be transmitted, which signal forms the response signal in which the interrogation device is provided with means for amplifying each response signal, until there is reached a predetermined threshold level of the low-frequency portions of the response signals, which are below the frequency of the periodic interrogation sweep, with the amplification that the low-frequency portions thereafter being so r

Abstract: This invention relates in general to a passive responder of a position finding system including at least one microwave antenna and a resonator body. The resonator body is mounted adjacent the rail of a railroad track and is connected to a microwave antenna which points upwardly such that it receives radiation from a transmitter carried by the train. The radiation opening of the receiving antenna is adjacent the rail head and the antenna is covered with a cover member comprising dielectric material which comes into contact with the wheel as each wheel rolls past. The contact of the wheel with the dielectric cover assures that ice, snow, and other foreign material will be continuously cleared from the receiving antenna so as to assure optimum operation of the transponder.