| 摘要 |
A device and method for line impendance measurement using a multi-frequency test signal (figure 1b, 1c) waveform in a signal injection technique featuring analysis of acquired line test response data. A multi-frequency test signal waveform (figure 1b, 1c) is injected into the subscriber line (figure 3), to obtain by data acquisition the line response in terms of voltage measurements, which are processed via a digital filter (14) to analyze a specific sine wave frequency. Using a multi-level rectangular wave signal as the test signal and analyzing at the dominant frequency derived from the rectangular signal, or other harmonics, it is possible to derive the line characteristics, including amplitude attenuation and phase shift, which constitute line impedance.
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