Fujitsu Corporation

Kazuyoshi Maruyama

Seiji Miyoshi

Misao Fukuda

Seiichi Yamato

Yutaka Awata

Masahiro Tanaka

Shinji Ohta

Masakazu Oi

Toshitsugu Kobayashi

Naoyuki Nakashima

Naoto Hamanaka

Kouji Tokiwa

Kinji Kawada

The invention provides a subscriber terminating equipment wherein a subscriber accommodated in a subscriber terminating package with which a fault occurs is switched to a relief package by constructing the same such that a common section selects a pair of subscriber terminating packages including a first subscriber terminating package and a second subscriber terminating package and allocates, if the first subscriber terminating package fails, the second subscriber terminating package as a bypass package for performing electric connection between a subscriber terminal and the relief package. The subscriber terminating equipment thus allows automatic switching of the relief package without using a switching package for exclusive use and allows replacement of the fault package without interrupting communication of a subscriber accommodated in the fault package.

Subscriber terminating equipment

A back wiring board which connects a printed board package to testers and an aggregated device of back wiring boards. A receiving portion receives a test demand signal from an external controller, a selector selects and connects one of the testers connected to adapter connectors for the connection to the printed board package based on the test demand signal. Group connectors connect a plurality of the back wiring boards to form a board group. The selector selects and connects one of the testers only to the printed board package connected to one of the back wiring boards within the board group based on the test demand signal.

Back wiring board and aggregated device

Initial training apparatus for use in a transmitter and receiver

Disclosed is a digital adaptive filter and a method of cancelling an echo component generated by a partial return of a transmission signal to a receiving side. The digital adaptive filter comprises: a main memory unit for storing a first echo replica which can be stored or read by using the parallel signal from a main tap unit as an address signal, at least one submemory unit for storing a second echo replica which can be stored or read by using the parallel signal from said subtap unit as an address signal, and an adding circuit for adding the first echo replica and the second echo replica. The second echo replica stored in the at least one submemory unit has a greater precision than the precision of the first echo replica stored in the main memory unit, and thus the accumulated error due to memory division can be reduced. Instead of or accompanied by the greater precision, the contents of the main memory are updated directly based on the error between the pseudo signal and an input signal or based on a step size corresponding to the error, depending on whether the error is relatively large or relatively small, respectively.

Digital adaptive filter and method of convergence therein

Growing community of inventors

Yokohama, Japan

Kazuyoshi Maruyama