| 摘要 |
1408420 Digital transmission; master and slave systems HUGHES AIRCRAFT CO 7 Feb 1973 [7 Feb 1972] 6053/73 Heading H4P In a two-way system comprising a central station and a plurality of remote stations having separate channels, i.e. transmission lines and/or frequencies for each direction of communication, the remote stations are divided into groups of similar transmission delay times, which groups are sequentially interrogated and responses received, during time intervals distinct for each group. The relative transmission delay times may be different from physical distance ratios due to differing transmission media. The arrangement may be applied to a radial or "common line" system. The groups are scanned in sequence, normally commencing with the group having the lowest delay, but other arrangements are envisaged; the sub-stations of any group may be addressed in any desired sequence. After the sub-stations of group 1 have been interrogated and their responses received at the central station, the next group is interrogated et seq. The substations of a given group may be interrogated at a periodicity substantially equal to twice the difference between time limits relevant to that group. The central station may include a digital computer which can provide system diagnosis, fault location &c. and the system may carry television, A.M. or F.M. broadcast signals. The central station may also include display-devices, paper tape machines and/or disc/drum memories known in the art. The transmission system may include repeaters. |
