Nec Corporation

Shin-etsu Chemical Co., Ltd.

Furukawa Co., Ltd.

Shigeaki Saito

Yoshihiro Kubota

Masaaki Iguchi

Toshiharu Matsueda

Toshikazu Koseki

A multiprocessor system including dual port memories (DPMs), each DPM used as a shared memory circuit for a host CPU circuit and one of sub CPU circuits. Each sub CPU writes an operation information thereof in a monitor information memory portion of an associated DPM after data write to a data portion of the DPM every data collection. The host CPU references the operation information in the monitor information memory portion and reads data from the DPM after a normal operation of the sub CPU is confirmed. When the sub CPU operates abnormally, the host CPU resets the sub CPU operating normally. A watch-dog timer monitors only operation of the host CPU.

Sub-CPU monitoring system including dual port memory

In a transmission system comprising a plurality of data transmission circuits connected through a transmission line to form a loop, a local transmission signal is transmitted from a selected one of the data transmission circuits to the other data transmission circuits through the transmission line to be returned back to the selected data transmission circuit. The selected data transmission circuit interrupts the local transmission signal by detecting an identification signal preassigned to the selected data transmission circuit in a signal selecting circuit and by putting a switch circuit into an off-state during the local transmission signal sent from the selected data transmission circuit.

Data transmission circuit capable of avoiding repeated reception and

The dopant body of arsenic for doping of a semiconductor substrate, e.g., silicon wafer, is a sintered body of a powder mixture comprising silicon arsenide, silica and, optionally, arsenic oxide in a specified proportion. The dopant body can be easily prepared and has various advantages over conventional elementary arsenic powder or a shaped body of silicon arsenide alone in respect of the high mechanical strength of the dopant body and absence of the problem of environmental contamination.

Dopant of arsenic, method for the preparation thereof and method for

A first terminal station (11) comprises a loopback signal producing circuit (L1.about.L5) for producing a loopback command signal having a predetermined number of command bits in each frame of a first PCM signal, and a signal multiplexing circuit (42) for multiplexing input signals and overhead bits into successive frames of the PCM signal with the command bits used as predetermined ones of the overhead bits. The command bits indicate a repeater station (21) which should loop back the PCM signal and a second terminal station (12) which should not loop back the PCM signal. The repeater station comprises a signal detector (45) for detecting the command bits indicative of loopback of the PCM signal at the repeater station to produce a loopback control signal, and a loopback carrying out device (63) responsive to the loopback control signal for looping back the PCM signal. The first terminal station further comprises a signal detector (65) for detecting like command bits indicative of loopback of a second PCM signal at the first terminal station to produce a terminal loopback control signal, and a loopback carrying out device (43) responsive to the terminal loopback control signal for looping back the second PCM signal as at least a part of the first PCM signal.

Growing community of inventors

Tokyo, Japan

Shigeaki Saito