Mitsubishi Electric Corporation

Yuta Takemoto

Yuichi Yamamoto

Akinori Fujimura

Toshiyuki Ando

Kazuo Kubo

Tomohiro Akiyama

Yoshiaki Konishi

Shinya Hirakuri

Junya Nishioka

Kazuyoshi Tsuji

An optical frequency control device includes: a detection circuit to receive first light including a first frequency, receive second light including a second frequency, modulate the first light with a local oscillation signal, and detect a differential beat signal between the frequency of sideband light included in the modulated first light and the second frequency; a light source control circuit to change the second frequency by frequency-dividing the differential beat signal with a first frequency division number, by frequency-dividing a reference signal with a second frequency division number, and by outputting a phase error signal indicating a phase difference between the frequency-divided differential beat signal and the frequency-divided reference signal; and a signal processing unit to set each of the first frequency division number and the second frequency division number according to the set value of a frequency difference between the first frequency and the second frequency.

Optical frequency control device, optical oscillation device, frequency conversion device, and radio wave generation device

An orientation direction control device includes: an orientation direction control information acquisition unit to acquire orientation direction control information for controlling an orientation direction in which a first optical communication terminal as a first transmission/reception device transmits and receives light; and a capture and tracking control unit as an orientation direction control unit to control an orientation direction in which a second optical communication terminal as a second transmission/reception device transmits and receives the light or a radio wave on the basis of the orientation direction control information acquired by the orientation direction control information acquisition unit.

Orientation direction control device, optical communication terminal, optical communication system, and orientation direction control method

Provided is a digital switch including: a plurality of input-side memories, which are arranged in a one-to-one correspondence with a plurality of input ports, and are configured to accumulate time-division multiplexed data; a plurality of output-side memories, which are arranged in a one-to-one correspondence with a plurality of output ports, and are configured to accumulate time-division multiplexed data; and a switch matrix configured to receive, as input, the time-division multiplexed data read out in every cycle from each of the plurality of input-side memories, and execute routing for selecting, in accordance with a connection control signal received from outside, any one of the plurality of output-side memories such that the time-division multiplexed data read out in every cycle is output from each of the plurality of output ports without causing a difference in delay, to output the time-division multiplexed data.

Digital switch, wireless communication device, control station, and wireless communication control method for switching a route of communication data

A multi-stage demultiplexing circuit in which a plurality of circuits each combining a selector and a frequency decimation circuit are connected is included. The selector selects one of input signals based on a control signal, and generates a plurality of output signals. The plurality of output signals output from the selector are input to the frequency decimation circuit, and the frequency decimation circuit performs frequency conversion processing, low pass filter processing, and down-sampling processing based on a control signal to generate an output signal. Two or more reception signals are input to the multi-stage demultiplexing circuit, and the multi-stage demultiplexing circuit executes demultiplexing processing based on a control signal so that an output signal that includes an unused band portion is prevented from being output downstream.

Demultiplexing circuit, multiplexing circuit, and channelizer relay unit

A delay measuring device of a communication system that includes the delay measuring device sequentially transmitting and receiving frames having a known frame length, and a measurement object device serving as an object for measuring a round trip time by the delay measuring device, includes: an RTT measuring unit to measure a round trip time with respect to the measurement object device a number of times using information for delay measurement in the frame; an RTT change detection unit to detect a change of a value of the round trip time based on the values of the round trip time thus measured; and an RTT determination unit to determine a value of the round trip time to be adopted, from among the values of the round trip time, based on the change of a value of the round trip time.

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Chiyoda-ku, Japan

Yuta Takemoto