| 摘要 |
A LAN cable tester circuit (100) is disclosed having measurement end circuit components (30) and shorting end circuit components (132). The measurement end circuit components (30) are conventional and include a multiplexer (34) having a current source (36) and voltage sensing circuitry (38) electrically coupled thereto. The multiplexer (34) also has a plurality of pairs of associated electrical conductors (14, 16) included in the cable (12) under test coupled thereto. The shorting end circuit components (132) include another multiplexer (150) having the opposite ends of the electrical conductors coupled thereto, and further having a differential voltage amplifier (152) and two current output differential amplifiers (154) electrically coupled thereto. The shorting end circuit components (132) provide for an active short that eliminates the effect of the on-resistance attributable to semiconductor integrated circuit multiplexers.
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