Device for increasing the safety with respect to transmission faults in an information transmission system
US4121208A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1977 |
| Grant date | Oct 17, 1978 |
| Priority date | — |
| Expiry date | Mar 11, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/753
- WIPO fieldMeasurement
- WIPO sectorInstruments
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 o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.