National Institute of Information and Communications Technology, Incorporated

Tokyo Institute of Technology

Tetsuya Ido

Yuichiro Yano

Motoaki Hara

Hiroyuki Ito

Masatoshi Kajita

A time synchronization network able to efficiently maintain time synchronization according to standard time is described. A communication device includes a time information output unit and a time synchronization unit. The time information output unit is configured to output time information with an internal clock that is stable. The time synchronization unit is configured to correct the time information of the time information output unit based on information on a time difference between the communication device and another communication device adjacent to the communication device.

Time synchronization network

A node includes: a communication module that recovers a clock signal of another node; a high-precision clock module; a first phase/frequency comparison module; a time estimation section that estimates time information of each node; a counter value correction section that corrects a counter value; a fractional PLL; a second phase/frequency comparison module; and a division ratio correction section that corrects a division ratio of the fractional PLL.

Time synchronization device and network

This atomic resonator for causing a resonance frequency by CPT resonance includes: a gas cell having alkali metal atoms enclosed; a photodetector configured to detect light having passed through the gas cell and convert the light to an electric signal; a high-frequency oscillator configured to receive the electric signal and output the signal after a frequency thereof is divided by two; and a laser light source configured to modulate and introduce, into the gas cell, light based on the signal output from the high-frequency oscillator. The high-frequency oscillator has an injection-locked frequency divider circuit including an acoustic resonator as an oscillation element.

Growing community of inventors

Tokyo, Japan

Tetsuya Ido