| 摘要 |
1502043 Testing insulated conductors COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS CIT-ALCATEL SA 31 March 1976 [16 April 1975] 12931/76 Heading G1U In detecting incorrect pairing of twisted pairs in a multi-wire telecommunications cable, a signal is injected into successive ones of the first wires of the pairs, and signals from the second wires of the pairs due to induction are detected. The cable has pairs ai, a<SP>x</SP>i;...an, a<SP>x</SP>n at one end and pairs bl, b<SP>x</SP>l;... bn, b<SP>x</SP>n at the other. These are connected to male multi-way connectors, which fit female connectors on the apparatus front-panel, Fig.2 (not shown). This connects ai ... an ie the first wires of the n pairs to the outputs of a demulti-plexer DM, and the corresponding second wires at the other cable end b<SP>x</SP>1... h<SP>x</SP>n to detector D1... Dn. A 10Hz oscillator 01 feeds a counter CT whose outputs provide the address inputs to the demultiplexer DM, which thus sequentially directs 2MHz signals from oscillator 02 to successive first wires ai ... an. The counter CT outputs are also de-coded D.C. to illuminate one of lamps L1-Ln on the front panel via outputs Sl-Sn, corresponding to the energized wire. Whichever second wire is twisted with the energized first wire provides an induced voltage to one of the detectors D1-Dn. That detector provides an output S<SP>x</SP>1 ... S<SP>x</SP>n to illuminate a second lamp on the front panel. These lamps are arranged, such that correctly paired wires illuminate lamps side-by-side, Figs.2, 3B, 4B, 5B, 5C (not shown). A comparator CP compares the de-coder D.C. output and the detector outputs and if these do not correspond to correctly paired wires, a low output to NOR-gate PN causes that gate to block oscillator 01, thus stopping further stepping, and the front-panel lamps stay illuminated to indicate a fault. The stepping is recommenced by operation of a push-button BD which actuates a monostable BM to give a high output, thus removing the blocking signal Ebto the oscillator. |
