Fujitsu Corporation

Kabushiki Kaisha Toshiba

Hiroshi Oikawa

Yuko Sato

Kazuhiro Yasuda

Keisuke Harada

Nobuhide Hachiya

Yuichi Nagaki

Yoshiaki Shibayama

Satoru Miyazaki

Tsutomu Yamada

Yoshitaka Eguchi

Takashi Murano

A feedback control device capable of continuously performing high-accuracy, stable control even in cases where any of multiple controllers for controlling a controlled system becomes incapable of control action. A controller (master controller) generates control data for stably controlling a heater by feedback control, controls the heater in accordance with the control data, and sends the control data to the other controller (slave controller). The slave controller receives the control data from the master controller but does not control the heater while the master controller is operating normally. If the master controller develops anomaly and becomes incapable of normal control action, the slave controller initiates feedback control of the heater in accordance with the control data received from the master controller immediately before the anomaly occurred, and controls the heater thereafter in accordance with control data generated thereby.

Feedback control device

A pre-emphasis control method automatically and appropriately performs the pre-emphasis of each wavelength in a wavelength division multiplexing communications system. Before instructing pre-emphasis for a transmitting unit, the optical power of an optical signal of each channel (wavelength) is increased/decreased by a predetermined value, and it is determined for each channel whether or not the difference between a Q value when the optical power is large and a Q value when the optical power is small, is larger than 0. Depending on the determination, that is, if the difference is larger than 0, then it is determined that the channel belongs to a linear area, and if the different is equal to or smaller than 0, then the channel belongs to a nonlinear area. If the Q value of each channel is to be improved by the pre-emphasis, then the optical power is increased for the channel in the linear area, and decreased for the channel in the nonlinear area.

Pre-emphasis control method in consideration of nonlinear deterioration

An optical amplifier to which an optical output power automatic attenuation circuit according to the present invention is applied, comprises: one amplifier board to and from which a WDM light is input and output; and a plurality of booster boards which supply pumping lights to the amplifier board, an ID pattern generated in an ID pattern generating circuit disposed in each of the booster boards is superposed on the pumping light to be sent to the amplifier board, an electric signal indicating a monitoring result of the pumping light in a light receiver disposed on the amplifier board is transmitted to each of the booster boards, it is detected in an ID coincidence detection circuit in each of the booster boards whether or not a received ID pattern contained in the electric signal is coincident with the generated ID pattern, and a connection condition of an output fiber is judged according to the detection result so that an output level of the pumping light is controlled. Thus, it is possible to detect with a simple configuration the erroneous connection of an optical fiber between each of a plurality of transmission sections and a reception section, thereby reliably preventing the light of high power from being emitted to the outside.

Optical output power automatic attenuation circuit for optical communication apparatus

In the thunder cloud observation system of the present invention, the vertical direction accumulated water content (VIL) is calculated by the VIL arithmetic operation unit from echo strength data obtained by the climate radar, the echo peak temperature is obtained by the echo peak temperature arithmetic operation unit with reference to altitude-temperature comparison data on the basis of high atmospheric climate data, the precipitation area is determined by the area determination unit from the VIL data, and the thunder cloud area generated within the precipitation area is identified from the echo peak temperature data. The thunder cloud area determined by the area determination unit is subjected to the correlation processes in terms of distance and overlapping area by the identification/tracking process unit, thus performing the identification/tracking, and the results of the processes of the area judgment unit and the identification/tracking process unit are displayed in the image display unit. Therefore, even a thunder cloud area regionally generated within a cloud expanding at a relative low altitude can be identified, and the area thereof can be detected and tracked.

Thunder cloud observation system

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Kawasaki, Japan

Hiroshi Oikawa