Calibration system at NICT Haruo Saito National Institute of Information and Communications Technology
Organization of NICT Content Calibration system Calibration system Carried in system and remote system Stuffs and so on BMC of our system Calculate uncertainty Budget sheet
Organization of NICT Organization President 5 Vice Presidents 7 Research Centers 7 Departments Location Headquarters Yokosuka Research Laboratory Kobe Research Laboratory Keihanna Research Laboratory ;Tokyo ;Kanagawa ;Hyogo ;Kyoto
Organization of NICT NICT New Generation Network Research Center Network Architecture Group Photonic Network Group Quantum ICT Group Information Security Research Center Advanced Device Research Group Space-Time Standards Group Tokyo Applied Electromagnetic Research Center New Generation Wireless Communications Research Center Kobe Advanced ICT Research Center Knowledge Creating Communication Research Center Universal Media Research Center Kanagawa Hyogo Kyoto
Four Research Projects Japan Standard Time Project Generation and maintenance of high quality Japan Standard Time (JST) and UTC (NICT) Dissemination of standard by various methods (LF radio, NTP, dial-up,... etc.). One method Calibrate Frequency Atomic Frequency Standards Project Develop and operate primary frequency standard and optical frequency standard systems. Satellite Time Control Projects Precise T&F transfer between ground and satellites (ETS-8 and Quasi-Zenith Satellite System). Space-Time Measurement Project R&D for precise T&F transfer and establishment of spatial reference frame by using TWSTFT, optical fiber transfer methods, and space geodetic techniques such as GPS and VLBI
Calibration service at NICT NICT Calibration scope is only frequency standard NICT performs two calibration services Carried in calibration service Remote calibration service Frequency Range 1 MHz, 5 MHz, 10 MHz Frequency Accuracy(BMC) 5 x 10-14 (Carried in system) 5 x 10-13 (Remote system)
BMC of Calibration services Quantity Instrument or Artifact Calibration Range Measure and Level or Range Best Measurement Capability (k=2) Remark Frequency standards 1MHz, 5MHz, 10MHz 5.0E-14 TI method Frequency Frequency standards 1MHz, 5MHz, 10MHz 2.5E-12 DF method Frequency standards 1MHz, 5MHz, 10MHz, or 1pps 5.0E-13 Remote
Block Diagram of Carried in Calibration System Ext. Ref. 5 MHz UTC (NICT) Time Interval Counter : DUT SR620 1,5,10 MHz 10 MHz SP ST Ext. Ref. 5 MHz UTC (NICT) Time DUTInterval Counter : 1,5,10 MHz SR620 CH.A (ST) DUT 1,5,10 MHz DUT 1,5,10 MHz Time Interval Measurement System Direct Frequency Measurement System
Remote Calibration System National Frequency Standard GPS satellite Frequency Calibration Concern Frequency Standard Satellite Time Comparison (GPS Common-View method) Standards which require Frequency calibration NICT Precision achieves 5.0x10-13 (per day)
Carried in Calibration System Temperature and humidity are controlled in a electromagnetic shielded room
Base station for Remote Calibration system Internet server 1 Application server Internet server 2 NAS Control PC Internet router Data server Multi-channel GPS receiver Temp. & Hum. Measurement unit UPSs
Status of quality system Satisfied ISO/IEC 17025 Accredited to ISO/IEC 17025 by NITE Pathway: Accreditation Body: Third party accreditation. NITE (National Institute of Technology and Evaluation)
Certification
Staffs Supervisor 1 Quality manager 1 Project leader 1 (Technical management ) Managers 2 ( Calibration 1, Reception 1 ) Staffs 3 ( Calibration 2, Reception 1 )
Number of calibrations and others The number of calibrations 30-40 / year Audits, Reviews Full audits : Every 2 years (They are performed by NITE)
Best Measurement Capability SI (Calculate Uncertainty) traceability UTC UTC(NMI) Distribution system Uncertainty of UTC Uncertainty of UTC(NMI) Uncertainty of Distribution Calibration system Uncertainty of Calibration
Uncertainty of UTC CIRCULAR T data Period of estimation d u 55039-55074 5.3x10**-15 0.5x10**-15 (2009 JUL 27-2009 AUG 31) the worst value in a period Uncertainty of UTC
Uncertainty of UTC(NMI) Uncertainty of UTC(NMI) consists of Uncertainty of UTC(NMI) in CIRCULAR-T The worst value of u A in a period Prediction of UTC(NMI) Uncertainty for 1 M CIRCULAR-T is published 1 month later Frequency stability of the source clock & System noise of the regulator (ex. AOG)
Uncertainty of UTC(NMI) in CIRCULAR-T CIRCULAR T data Uncertainty/ns ua ub u NICT (Tokyo) 0.7 4.6 4.7 the worst value in a period 1 day averaged uncertainty =u A /86400/5x 5
Prediction of UTC(NMI) Uncertainty for 1 month Frequency stability of the source clock Frequency stability for 1 month Ex. 5071A (agilent teck.) is 1.0E-14 H-maser (Anritu) is <= 1.0E-14 System noise of the regulator System noise for 1 month Ex. AOG is 3E-13/86400/30
Uncertainty of Distribution Uncertainty of Distribution consists of System noise of distribution amplifiers for UTC(NMI) Stability of amplifiers (ex. Catalog data) System noise of the cable for distributing UTC(NMI) Thermal noise, exogenous noise, and so on (ex. Catalog data, measured data)
Uncertainty of Calibration Uncertainty of calibration methods Ex. Method of Time interval measurement, Method of Direct frequency measurement, etc. Factors for uncertainties Gate time Measurement number of times Ability of using counters and so on
Total uncertainty Total uncertainty is combined by the above data Total uncertainty is a square-root of sum of squares of the above data Expanded uncertainty computed by multiplying the total uncertainty by k (coverage factor =2)
Budget sheet of our system (1) Uncertainty of UTC 8.0E-16 Worst value in 2008 Uncertainty of UTC(NICT) Uncertainty of UTC(NICT) in CIRCULAR-T 3.6E-15 0.7ns x SQRT(5) / (86400 x 5) Prediction of UTC(NICT) Uncertainty for 1 Month Frequency stability of the source clock 1.0E-14 Stability of 30days in CIRCULAR-T System noise of the AOG 6.7E-20 3E-13/86400/30/SQRT(3)
Budget sheet of our system (2) Uncertainty of Distribution System noise of distribution amplifiers 1 st amplifier and 2 nd 3 rd 1.7E-17 amplifier 3.3E-17 amplifier Temp. coefficient; 0.5ps/deg, Temp. variation; 0.5 deg, Averaging time; 24 hours Temp. variation; 1.0 deg System noise of the cable for distributing 7.2E-17 Temp. coefficient; 0.04ps/deg, length; 60 m, Temp. variation; 5.0 deg, Averaging time; 24 hours,
Budget sheet of our system (3) Uncertainty of calibration methods (TI method) Counter Uncertainty 5.2E-15 Measurement error; 100ps, Measurement interval; 1440s, Number of measurements; 60 Frequency source Uncertainty 5.2E-16 Frequency stability; 4.0E-15(1440s), Number of measurements; 60 Relative combined uncertainty; Expanded uncertainty(k=2); Actual Expanded uncertainty 1.25E-14 2.5E-14 5.0E-14
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