Mitsubishi Electric Corporation

Masataka Imao

Eiji Matsuo

Aki Kaizu

Aki Oya

An optical signal generation device in an optical communication system includes a control signal manager that outputs the number of information sequences and control signals, a timing manager that outputs a timing signal, signal multiplexers that generate multiplexed signal sequences by multiplexing in a time-division manner transmission information sequences and the control signals, pulse converters that convert the multiplexed signal sequences to pulse signal sequences, and transmission processing units that send transmission signal sequences whose intensities correspond to values of the pulse signal sequences. Each control signal includes an identification signal allowing each transmission information sequence to be identified, the timing signals change their values on a cycle of the minimum pulse width of the pulse signal sequences, and time positions at which values of the N timing signals vary are different from one another.

Optical communication system, optical signal generation device, and optical signal reception device

A receiving device includes: a receiver that receives a signal including PPM symbols; a clock generator that generates a clock for sampling; an A/D converter that digital-converts the received signal; a reference position detector that detects a leading position of the PPM symbols based on data from the A/D converter; and a clock error detector that detects a clock error. The clock error detector includes: a pulse position detector that detects a pulse position in the PPM symbols based on data from the reference position detector and A/D converter; a position error calculator that calculates a deviation of the pulse position based on data from the reference position detector, A/D converter, and pulse position detector; and a clock error calculator that calculates the clock error based on data from the position error calculator. The receiving device varies a frequency of the clock based on data from the clock error calculator.

Receiving device and receiving method, and transmitting/receiving system

Provided are a reception device, a reception method and a transmission reception system capable of reducing the influence of distortion in a received signal and achieving high demodulation performance without performing a computation process having a great amount of calculations. The reception device receives a signal containing a known signal part and a data part, and includes a conversion unit that converts the signal received by a reception unit into a digital signal, a region determination unit that determines a nonuse region which is a periodic region containing distortion in the digital signal, on a basis of a first digital signal in the known signal part contained in the digital signal and a known signal held in advance, and a demodulation unit that performs demodulation on the digital signal by using a second digital signal in a region other than the nonuse region in the digital signal.

Reception device, reception method, and transmission reception system

A diversity receiving device includes receiving circuits, a diversity combining unit, and an oscillation controller. The receiving circuit performs frequency conversion of an analog received signal obtained at a first receiving system, by using a plurality of lower-side oscillation-frequency signals supplied from a first local oscillator, to generate a plurality of lower-side low-frequency signals, adds up the plurality of lower-side low-frequency signals to generate a first addition signal. The receiving circuit performs frequency conversion of an analog received signal obtained at a second receiving system, by using a plurality of higher-side oscillation-frequency signals supplied from a second local oscillator, to generate a plurality of higher-side low-frequency signals, and adds up the plurality of higher-side low-frequency signals to generate a second addition signal. The oscillation controller controls lower-side oscillation-frequencies so that frequency bands of the plurality of lower-side low-frequency signals become adjacent to one another and controls higher-side oscillation-frequencies so that frequency bands of the plurality of higher-side low-frequency signals become adjacent to one another.

Diversity receiving device and diversity receiving method

It is an object of the present invention to provide a radio signal demodulating device in which fluctuation follow ability of transmission channel environment is improved. The radio signal demodulating device according to the present invention receives the amplitude of an information signal in which known pilot signals are multiplexed, as a radio signal modulated in proportion to the time change of frequency of a carrier wave The radio signal demodulating device according to the present invention includes a frequency converting unit, a signal combining unit, a first pilot signal extracting unit, a second pilot signal extracting unit, a first pilot orthogonal signal generating unit, a second pilot orthogonal signal generating unit, a first error signal generating unit, a first weight factor updating unit for calculating a weight factor to be used in the signal combining unit, by using a first pilot orthogonal signal and a first error signal obtained by the first error signal generating unit.

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Tokyo, Japan

Masataka Imao