1. National Institute of Information and Communications Technology Development of the time dissemination technology for the radio controlled watches and clocks used by the network Tsukawa Iwama, Fumimaru Nakagawa, Kuniyasu Imamura, Hiroshi Toriyama, Akihiko Machizawa, and Hideo Maeno

2. National Institute of Information and Communications Technology Introduction NICT has distributed Japan Standard Time and national frequency standard. ↓ National service Low Frequency Standard Time and Frequency Transmission Stations in Japan （ＪＪＹ） / Radio controlled watches and clocks ↓ Problem Difficult to receive radio waves in inappropriate environments such as inside of buildings ↓ Correspondent method Promotion of distribution in the network ↓ Plan of research and development Development of the repeater using Network Time Protocol （ A small and prototype repeater ） ↓ Fundamental tests （ A field strength measurement and a functional check ） Utilization ・ Spread in Japan Application ・ Spread in Southeast Asia, such as Thailand (Distribution of a local time)

3. National Institute of Information and Communications Technology Japanese Low Frequency Standard Time and Frequency Transmission Stations (JJY)

4. National Institute of Information and Communications Technology Various kinds of repeaters (relay system) The conventional system Booster system Time link system The relay system in a building The system distributed to intranet This system, Future system Repeater system using NTP The repeater system using HTTP (near future)

5. National Institute of Information and Communications Technology The conventional system The relay system in a building ： The system which carries out frequency conversion of the received signal, and is indoors broadcast again by LF. http://www.nippon-antenna.co.jp/news-release/jjy_sys.htm Nippon Antenna 400 MHz Time link system : An original link system SEIKO PRECISION INC. http://www.seiko-clock.co.jp/seiko/time.html Receive 40 kHz or 60 kHz Transmission 60 kHz or 40 kHz Booster system ： Frequency conversion and retransmission CITIZEN HOLDINGS CO., LTD （ Rhythm Watch Co.,Ltd. ） http://www.citizen.co.jp/ LF Stations Standard time and frequency signal Standard time and frequency signal Standard time and frequency signal Antenna-installed in rooftop of the building Radio controlled watches and clocks

6. National Institute of Information and Communications Technology Image of research and development plan for repeater Home, Hotel, etc… Repeater by NTP NICT JST Internet NTP server : NICT, NIMT, Public, etc. Inside of buildings, underground, and …, in any countries with no LF station Developed repeater Ntp.nict.jp Transmitting equipment for small areas (Inside of airport buildings, theme parks, universities corporate sites, and etc. )

7. National Institute of Information and Communications Technology The subjects of development and utilization Check the Extremely Low Power Radio Station Make a presentation of the technical standard to the clock industry in order to generalize the repeater using NTP. （ idea by NICT ） Development of the model of a usable level Make a proposal of application developed for the repeater using a network （ For example ： Wireless LAN, USB type, HTTP, and PLC (Power Line Communications) ) Spread in Southeast Asia ： in collaboration with NIMT, make a proposal of the repeater which is suitable for Thailand

8. National Institute of Information and Communications Technology Development of prototype repeaters Developed in 2006 At first, the prototype repeater generates a time code on a personal computer (PC). Next, time information is sent out to the transmitting section and almost the same time code as JJY is transmitted from an antenna. The timing from PC is maintained at the accuracy of NTP. And the time code and timing which are received are sent to D/A of a transmitter. A transmitter sends out Extremely Low Power from an antenna. In this fiscal year, a basic check of operation is carried out. In addition, We measured field strength. coil type 3.2 cm Transmitter Loop type 34 cm The antenna of two types is made as an experiment. PC NTP server Antenna Block diagram

9. National Institute of Information and Communications Technology Small repeater development Developed in 2006 The small repeater (one apparatus) was developed based on the know-how studies in the preceding year. The software developed with PC was becoming cheaper CPU of one chip. The NTP client operates with free software proprietary software. Therefore, repeater itself see to operate by connecting an Ethernet cable. On the other hand, We checked that the right time code was transmitted in the accuracy of NTP. Accuracy is less than 10 msec. 30 turns

10. National Institute of Information and Communications Technology Field strength measurement Commercial booster type repeater Is it transmitter with extremely low power? Prototype repeater We measure FS with two kinds (a loop type and coil type) of test antennas. We investigated whether it could use as Extremely Low Power Radio Station. Small repeater The performance of the loop antenna in a plastics case needs to be checked.

11. National Institute of Information and Communications Technology The result of field strength measurement of a booster 40kHz 60kHz 40kHz Experiment scenery in a large-sized electric wave darkroom 電波法 ●40kHz ●60kHz The formula in Radio Law of Japan (54-(24-log 10 F) ［ dBμV/m ］ ) F is the frequency of the unit of MHz. Three-set measurement The maximum distance, which a radio controlled clock adjusts its time, is about 15m. Japanese radio low Distance [m] Field Strength [ dBμV/m ]

12. National Institute of Information and Communications Technology The result of field strength measurement of a prototype Diameter:34 cm Diameter3.2 cm Coil type Antenna Loop type Antenna Turns 40kHz ： 14 60kHz ： 11 Range is about 20 m. Japanese radio low Distance [m] Field Strength [ dBμV/m ] 2007/06/04 Range is about 6 m. Turns 40kHz ： 88 60kHz ： 66

13. National Institute of Information and Communications Technology 電波法 ●40kHz ●60kHz The result of field strength measurement of a small type 2008/8/14 ２台測定 105 mm x 90 mm ３０ turns Japanese radio low Distance [m] Field Strength [ dBμV/m ] Two-set measurement Range is about 7 m.

14. National Institute of Information and Communications Technology Conclusion Development to the utilization level of a repeater was achieved. The check of Extremely Low Power transmitter was performed. The application sample in future was shown. The clock companies started considering mass- production. NICT exhibited the small repeater to ITU Telecom Asia 2008 in Thailand and National Science and Technology Fair 2009. NICT aims at spread in Southeast Asia of the radio controlled watches and clocks.