| 摘要 |
A two-ended, line driving and receiving/tone signal analysis system performs line connection verification applying a low-distortion, low-amplitude test signal to one end of a cable pair under test and monitoring the response of a remote end wireline pair. The test signal frequency is on the order of 110 Hz, which avoids domestic and foreign AC power signal frequencies and is spectrally equidistant from their harmonics. It also avoids ringing frequencies for POTS lines, and remains safely below the 350 Hz lower limit of POTS and other telephone line systems. In response to an application of the 110 Hz test signal to tip and ring segments of a wireline pair at one end of the cable bundle, the energy of the 110 Hz component, as well as that of two other "spectrally nearby" (slightly higher at 112 Hz and slightly lower at 108 Hz), are measured at a tip and ring pair at the far end of the cable plant. If the magnitude of a Fourier component of the received 110 Hz test signal for a Fourier correlation operation cycle (FCOC) is more than a prescribed differential greater than the magnitudes of the two nearby frequencies, it is inferred that the remote tip and ring pair is the same wire pair as the wireline pair at the one end of the cable, thereby identifying the two ends of the same wireline pair.
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