| 摘要 |
1,188,228. Digital transmission systems. SIEMENS A.G. 27 Sept., 1968 [28 Sept., 1967], No. 46158/68. Heading H4P. [Also in Division G4] A process for testing a transmission path comprises transmitting data through the path, the data comprising a word having free bitlocations. A predetermined one of the free bit-locations is supplied with a parity bit. At least one check unit downstream of that supply checks the word on the basis of the parity bit and produces a further parity bit which is entered into a further free bit-location of the word. Devices 1 such as analog/digital converters or pulse counters supply data to an input device 2. The data can be supplied with a parity bit or have one supplied at the input device. A check unit 6 is used to check the word against the parity bit and to insert a further bit to maintain the parity, the further bit being introduced into a predetermined location. The data is then passed, via multiplexors and decoders if required, to a device controlling data input to a computer 5. One or more further monitoring circuits 7 check the parity of the word and each inserts a further parity bit in predetermined locations. The transmitted word is stored in the computer. The parity bits show whether a fault has occurred and in which section of transmission path it occurred. By transmitting further words for comparison it is determined whether the fault is temporary or requires replacement of circuitry. More complicated codes than a simple parity bit can be used. |
