Method and apparatus for detecting missing micro-filter

摘要

The present invention provides a method and apparatus to detect a missing micro-filter. In embodiments, the detection is performed by measuring the distortion caused by an unfiltered telephone device using a SELT (Single Ended Line Test) technique. According to certain aspects, the signal used to perform the distortion measurement is designed such that it causes minimal impact on vectored lines within the same cable. Embodiments of the invention first determines the estimated loop length, then uses the loop length to select a set of signal parameters that will be used to perform the distortion measurement. The parameters to be selected include transmit frequency band and PSD level. According to further aspects, embodiments of the invention include automatically running a missing filter test immediately following a line drop to determine if the line drop was caused by a missing micro-filter.

主权项

1. A method to detect a missing micro-data filter, comprising:
selecting a probe signal having a transmit signal band and at least one separate monitor band; performing a single-ended line test (SELT) by transmitting the probe signal on a line and simultaneously measuring a reflection of the transmitted probe signal; calculating distortion in the at least one monitor band, wherein calculating distortion comprises measuring the spectral energy in the at least one monitor band; and declaring a missing micro-filter based on the calculated distortion.