Méthode de réduction de la diaphonie dans un câble de télécommunications blindé.

International audienc

Crosstalk Models for Short VDSL2 Lines from Measured 30 MHz Data

<p/> <p>In recent years, there has been a growing interest in hybrid fiber-copper access solutions, as in fiber to the basement (FTTB) and fiber to the curb/cabinet (FTTC). The twisted pair segment in these architectures is in the range of a few hundred meters, thus supporting transmission over tens of MHz. This paper provides crosstalk models derived from measured data for quad cable, lengths between 75 and 590 meters, and frequencies up to <inline-formula><graphic file="1687-6180-2006-085859-i1.gif"/></inline-formula> MHz. The results indicate that the log-normal statistical model (with a simple parametric law for the frequency-dependent mean) fits well up to <inline-formula><graphic file="1687-6180-2006-085859-i2.gif"/></inline-formula> MHz for both FEXT and NEXT. This extends earlier log-normal statistical modeling and validation results for NEXT over bandwidths in the order of a few MHz. The fitted crosstalk power spectra are useful for modem design and simulation. Insertion loss, phase, and impulse response duration characteristics of the direct channels are also provided.</p

Vectored DSLs with DSM: The road to Ubiquitous Gigabit DSLs

Abstract- This paper investigates the Digital Subscriber Line (DSL) data-rate increases possible with the Dynamic Spectrum Management (DSM) methods known as Level 3 Vectoring and Level 2 Band Preference. A suggested sequence of increasingly binder-adaptive DSM steps appears herein to assist and motivate DSL service providers and equipment vendors to progress in use of DSM. In particular, studies of bounds of spectral balancing find Band Preference as a practical method that provides the highest possible Level 2 performance in bundled or unbundled DSL environments. Investigations of vectoring begin with differential vectoring and show very high DSL data rates. These data rates increase further through the use of full-binder vectoring, leading to projections of feasible DSM vectored implementations of multi-100Mbps DSLs