| 摘要 |
PURPOSE:To attain discrimination of continuity and polarity of a communication line and to attain ease of a cable conductor cross reference work by extracting optional two point signals on the communication line so as to discriminate the correlativity of the two signals. CONSTITUTION:An optional point on a communication line Pr is nipped by a conductive clip Hg and a communication signal is extracted by differential amplifiers DA1, DA2. A signal from the amplifier DA2 is multiplied by MP with a signal of the amplifier DA1 through an attenuator ATT and a phase shifter Fs and the polarity of the output E is displayed on MT. If a communication line clipped by a clip Hg is different, the polarity of the output of the multiplier MP is random but when the same communication line is picked up, the polarity of output of the multiplier MP is always constant. When the polarity of the cable conductor clipped by the clip Hg is coincident, a positive output is obtained and if the polarity is inverted, a negative output is obtained, then the polarity of the cable conductor is discriminated. |
