FDR SINGLE ENDED LINE TESTING (SELT) SYSTEM AND METHOD FOR DSL MODEMS

摘要

A single ended line testing (SELT) method using a Frequency-Domain Reflectometry (FDR) that uses one or more echo signals originated by transmitting a periodic multi-tone signal, e.g., a REVERB signal, reflected from the hybrid and analyzes it in frequency domain. The REVERB signal is part of the ADSL modem training signal. Therefore the invention can be simply implemented as part of the DMT-based DSL modem because transmitting a multi- tone signal and capturing the frequency response of echo are readily available through the inverse fast Fourier transform/fast Fourier transform (IFFT/FFT) blocks that are used for modulation and demodulation.