Fujitsu Corporation

Hiroshi Nishida

Yoshihiro Watanabe

Kenichi Okabe

Hideaki Tazawa

Yoshiharu Kato

Satoshi Kakuma

Kosuke Komaki

Shiro Uriu

Masami Murayama

Takashi Hatano

Yoshihiro Uchida

Mikio Nakayama

Jun Itoh

Taku Saito

Yasuhiro Aso

Naoyuki Izawa

Jin Abe

Eiji Ishioka

Noriko Samejima

Makoto Shimizu

Shigeru Sekine

Hirofumi Araki

Satoshi Esaka

Miyuki Kawataka

Fumio Hirase

Taketo Endo

Yoshiyuki Karakawa

Yasuhiro Nishikawa

Shinichi Araya

Nobuyuki Tsutsui

Atsuko Suzuki

Shouji Kohira

Hiromi Yamanaka

Yoshihisa Tsuruta

Atsushi Kagawa

Masato Kobayashi

Sumie Morita

Tatsuya Oku

Masato Hashizume

Shuzo Matsushita

Yasusi Kobayasi

Yasusi Kobayashi

An optical transmission apparatus includes: a coherent detector configured to receive light including different polarization components from an optical transmission path, and perform coherent detection of received light including the different polarization components; an adaptive equalizer configured to adaptively equalize, by a digital filter, a complex electric signal for each of the polarization components obtained by the coherent detection, a gain value for controlling an amplitude of the complex electric signal being applied to the complex electric signal; and a polarization dependent loss monitor configured to determine a polarization dependent loss of the optical transmission path, based on a correction filter parameter obtained by correcting a filter parameter of the digital filter according to the gain value, the filter parameter being adaptively updated by an adaptive equalization of the adaptive equalizer.

Optical transmission apparatus, optical transmission system, and polarization dependent loss monitor

An optical transmission apparatus includes: an optical receiver configured to receive an optical signal; a variable optical attenuator configured to adjust a power of the optical signal to be input to the optical receiver according to a variable attenuation amount; and a controller configured to control the attenuation amount of the variable optical attenuator based on an electrical signal obtained by performing a coherent detection and a photoelectric conversion on the optical signal received by the optical receiver.

Optical transmission apparatus and method for controlling optical power

A transmission apparatus includes: a first input-output unit; a second input-output unit; a third input-output unit located in a first direction that is a transmission direction from the first input output unit and the second input-output unit; and a switch coupled to the first input-output unit, the second input-output unit, and the third input-output unit, wherein the first input-output unit requests the third input-output unit via the switch to notify in a second direction opposite to the first direction of a defect upon detecting the defect, wherein the third input-output unit transmits defect information indicating the defect to one of the first input-output unit and the second input-output unit via the switch in response to a requesting from the first input-output unit.

Transmission apparatus and transmission method

A transport apparatus configured to transport a main signal received via one of a plurality of ports to any of the plurality of ports, the transport apparatus includes: a plurality of main signal processing circuits configured to extract a monitoring control signal from the main signal, the plurality of main signal processing circuits being provided to correspond to the plurality of ports, respectively; a monitoring controller configured to receive the monitoring control signal from the plurality of main signal processing circuits; and a serial interface configured to connect the plurality of main signal processing circuits with the monitoring controller on a ring-shaped bus to transfer a serial frame, wherein the serial frame has a mapping field to which the monitoring control signal is mapped.

Transport apparatus and method of transmitting monitoring control signal

A transmission apparatus includes a detector to receive a multiplexed signal including a plurality of signals having different frame periods and detect switching information included in the multiplexed signal; a sorter to sort a plurality of pieces of detected switching information into one or more groups according to types of corresponding signals; an adjuster to adjust an order of transferring the switching information sorted, according to a period with which the switching information is received; a transfer unit to transfer the plurality of pieces of switching information sorted, based on a result of the adjustment performed by the adjuster; a controller to generate path setting information to set transmission paths of the signals based on the plurality of pieces of switching information transferred from the transfer unit; and a switch unit to set the transmission paths based on the path setting information generated by the controller.

There is provided an error correction control method of a transmission system on which a signal is transmitted from a first transmission apparatus to a second transmission apparatus, the error correction control method including: transmitting a signal for a mode change request to change an error correction mode from the second transmission apparatus to the first transmission apparatus; transmitting signals having a change timing value in a specific order with a specific period from the first transmission apparatus to the second transmission apparatus when the first transmission apparatus receives the mode change request; changing the error correction mode of the first transmission apparatus when the change timing value to be transmitted becomes a specific value in the first transmission apparatus; and changing the error correction mode of the second transmission apparatus in response to the change timing value received with the specific period from the first transmission apparatus.

Transmission system and error correction control method

A communication apparatus having a clock interface unit supplying a clock signal for synchronization, includes a clock extracting section for extracting a clock component from a receive signal, a decoding section for generating a decoded signal by decoding in a predetermined encoding form the clock component extracted by the clock extracting section, a frame converting section for creating a receive frame by converting the decoded signal to a frame in a predetermined frame form, a determining section for determining whether the predetermined encoding form and the predetermined frame form are right or not on a basis of the receive frame, a setting section for performing setting regarding the clock signal on a basis of the encoding form and frame form determined to be right by the determining section, and a clock signal output section for outputting the clock signal generated on a basis of the setting by the setting section.

Communication apparatus having clock interface

A switch station including an ATM switch; a memory storing control data for operations of the switch station; an intra-station device, accommodating a subscriber line, performing communication operation on subscriber ATM cell; a control processor generating control information in link access protocol (LAP) format; and an interface unit converting LAP control information into ATM cell to the intra-station device through the ATM switch, wherein the control information is communicated according to LAP, the intra-station device receives the control information and transmits a direct memory access request to obtain control data stored in the memory, the interface unit obtains and converts the data format of the control data into ATM cell to transmit to the intra-station device through the switch, and the intra-station device performs the communication operation on the subscriber ATM cell based on the control data received through the switch.

Intra-station control system for connectionless communications system

The quality and performance of the connectionless communications system are improved. When a BOM is received, the destination address DA of the L3-PDU stored in the payload of the BOM is retrieved, and the tag information is obtained from the DA (S,). The output message identifier MID is reserved (S,), and the tag information and output MID are assigned to the BOM (S,). Then, the tag information and output MID are written to the table. When a COM is received, the tag information and output MID are retrieved using the MID of the COM as a key, and the information is provided for the COM (S,and S,). When an EOM is received, the tag information and output MID are retrieved using the MID of the EOM as a key, and the information is provided for the EOM (S,and S,). Then, the output MID is released (S,).

Connectionless communications system, its test method, and intra-station control system

An ATM exchange system which handles fixed-length cells, such as an ATM exchange, is designed in such a manner that even when a failure occurs particularly in an interface unit or an ATM switch section, downstream stations can be informed of the failure reliably and that when some failure is detected, counting of a charge counter is disabled to always ensure proper charging. For a method of matching between software and hardware in the ATM exchange system including the ATM switch section having a plurality of line associated sections and firmwares associated with those line associated sections, and a call control processor for controlling the ATM switch section, identifiers of an SVC (Switched Virtual Channel) call and a PVC (Permanent Virtual Channel) call are given to connection information of software on the call control processor, connection data affixed with the identifier of the SVC call is released only on the software on the call control processor during a restarting process of the call control processor, and a request to release the SVC call to all the line associated sections in the hardware of the ATM switch section, whereby matching of path information between the software on the call control processor and the hardware of the ATM switch section is performed.

Method for attending occurrence of failure in an exchange system that exchanges cells having fixed-length, and interface unit and concentrator equipped in the exchange system using the method

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Kawasaki, Japan

Hiroshi Nishida