Ien Time and Frequency Metrological Activity and Support to User Needs

T71e increased importance ojtime andfrequency mmolog~ in scientific and indushial applications has raised a request of a wider speckurn of services from the national standad laboratories. On the metrological side, a new generaion offrequency standards and the worldwide availabilitJ of eatrenelg accurate time dissemination sgstems bave opened new perspecfives of research and applications. The IEN Time and Frequency Lcrboraorg, charged with the recrlizcllion and dissemhiion oj the ItcJian standud time, in order to meet the requests of different users h s been engaged in differenl activities that a n m i d in this paper, where also the future p o s s i b i h are discussed. k INTRODUCTION The IEN Time and Frequency Laboratory, which has been charged by law in 1991 with the research, realization, and dissemination of the SI unit of time for Italy, has been involved since the seventies in the realization of a local UTC time scale, known as UTC(ZEN), and has been contributing with its cesium clocks to the ultimate reference of time UTC established by BIPM. The traceability of UTC(1EN) to the international time scale is realized by two GPS receivers, following the complete BIPM common-view schedule for Europe, and with the software updated according to the technical directives of the CGGTTS Working Group. The dissemination of UTC(1EN) to the real-time user is performed in different ways, as described in the following, with accuracies ranging from 0.05 s to 100 ps. As regards a major issue coming from the industrial market, that of traceability of secondary standards to the national standard of time and frequency, a variety of solutions are offered through different synchronization techniques, namely coded time signals, passive TV, GPS comparisons, and clock transportation, with uncertainties, at the 1 u level, ranging from I x I O ~ to 5x10-14. Another means of dissemination b the accreditation activity performed by IEN for the Italian Calibration Service (SIT) that has been a response of the National Metrology Institutes (NMI) to the hugely increased request of traceability to the $1 units coming from the calibration and test laboratories as a consequence of the implementation in industries of Quality Assurance Standards, such as IS0 9000 series and EN 45001. In this framework, interlaboratory comparisons are organized to check the competence level of the laboratories accredited for frequency and to ensure the traceability to the national standard, therefore completing the Regional Metrological scheme, foreseen to be extended worldwide in the near future, establishing a reliable comparability of measurements, results that will be of great help in removing the technical barriers to the international trade. Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE DEC 1996 2. REPORT TYPE 3. DATES COVERED 00-00-1996 to 00-00-1996 4. TITLE AND SUBTITLE IEN Time and Frequency Metrological Activity and Support to User Needs 5a. CONTRACT NUMBER