Device for increasing the safety with respect to transmission faults in an information transmission system
First Claim
1. In 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;
- the interrogation device transmitting an interrogation signal, which can be periodically swept through a predetermined frequency band, preferably in the microwave range;
the interrogation device receiving, during a read operation of at least two periods from the passive response device, a frequency-selectively reflected interrogation signal, in accordance with a k-digit information item to be transmitted;
the combination of means for amplifying such a reflected interrogation signal received by the interrogation device;
means for monitoring the level of the low-frequency portions of such a reflected interrogation signal lying below the sweep frequency of the interrogation device and for reducing the amplification of said amplifying means if the level of such low frequency portions reaches a predetermined threshold value, whereby such low frequency portions do not undesirably exceed such threshold value;
switch means for controlling the through-connection of the response signal to subsequent devices; and
control means connecting said monitoring and switch means, for controlling the latter to prevent passage of a transmitted information item in the presence of a decreasing and/or increasing level of such low frequency portion.
0 Assignments
0 Petitions
Accused Products
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 reduced that they do not undesirably exceed the threshold value, and means being provided for preventing a through-connection of a transmitted information item in the presence of a decreasing and/or increasing level of such low-frequency portion.
5 Citations
8 Claims
-
1. In 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;
- the interrogation device transmitting an interrogation signal, which can be periodically swept through a predetermined frequency band, preferably in the microwave range;
the interrogation device receiving, during a read operation of at least two periods from the passive response device, a frequency-selectively reflected interrogation signal, in accordance with a k-digit information item to be transmitted;
the combination of means for amplifying such a reflected interrogation signal received by the interrogation device;
means for monitoring the level of the low-frequency portions of such a reflected interrogation signal lying below the sweep frequency of the interrogation device and for reducing the amplification of said amplifying means if the level of such low frequency portions reaches a predetermined threshold value, whereby such low frequency portions do not undesirably exceed such threshold value;
switch means for controlling the through-connection of the response signal to subsequent devices; and
control means connecting said monitoring and switch means, for controlling the latter to prevent passage of a transmitted information item in the presence of a decreasing and/or increasing level of such low frequency portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- the interrogation device transmitting an interrogation signal, which can be periodically swept through a predetermined frequency band, preferably in the microwave range;
Specification