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Proceedings of the IEEE

Issue 5 • Date May 1972

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Displaying Results 1 - 25 of 41
  • [Front cover and table of contents]

    Publication Year: 1972, Page(s): c1
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    Freely Available from IEEE
  • Scanning the issue

    Publication Year: 1972, Page(s):476 - 478
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  • International time and frequency coordination

    Publication Year: 1972, Page(s):479 - 487
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1007 KB)

    The significant advances in the development of international coordination in time determination and dissemination are briefly reviewed. Before 1955, time was determined exclusively by astronomical observations and international cooperation was primarily the concern of the International Astronomical Union (IAU). In the past 15 years, an independent time scale, based on atomic phenomena, has been re... View full abstract»

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  • The foundation of time and frequency in various countries

    Publication Year: 1972, Page(s):487 - 493
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    The assistance available to a country desiring to establish reference bases in time and frequency suitable for its own needs is discussed. The emphasis is placed on helping countries with little prior experience in the field. An outline of the international organizations interested in time and frequency is given. The technical assistance programs which might be called upon by a country are mention... View full abstract»

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  • Standard time and frequency generation

    Publication Year: 1972, Page(s):493 - 501
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1051 KB)

    The basic properties of atomic primary frequency standards are reviewed. A continuously running frequency source combined with counting, storage, and display devices results in a clock. Time scales are obtained by setting clocks with respect to a convenient origin. The accuracy of a primary frequency standard is a combined theoretical and experimental assessment of the uncertainties of all known p... View full abstract»

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  • Characterization and concepts of time-frequency dissemination

    Publication Year: 1972, Page(s):502 - 521
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2904 KB)

    Fundamental considerations that arise in designing a time or frequency dissemination system, are discussed and some dissemination methods are surveyed. A section on "Signal design for time and frequency dissemination" briefly summarizes radio propagation characteristics, discusses time signal format design, and considers how noise affects time and frequency signals. We point out fundamental techni... View full abstract»

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  • Path delay, its variations, and some implications for the field use of precise frequency standards

    Publication Year: 1972, Page(s):522 - 529
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (702 KB)

    In order to assess the practical utility of high-performance frequency standards in field applications, the effect of the propagation medium must be taken into account. After a brief summary of noise processes, a discussion of the performance of current frequency standards is given, together with an estimate of the relative cost, reliability, and necessary system support for each type. Literature ... View full abstract»

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  • Precise time and frequency dissemination via the Loran-C system

    Publication Year: 1972, Page(s):530 - 539
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1925 KB)

    The Loran-C Navigation System is described in terms of its characteristics as a precise time and frequency dissemination system. The technique employed in timing a Loran-C chain is described, and user techniques are addressed including economic considerations. The accuracy available for both ground-wave and sky-wave transmission modes is shown to be a function of the low-frequency propagation fact... View full abstract»

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  • VLF timing: Conventional and modern techniques including omega

    Publication Year: 1972, Page(s):540 - 551
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1680 KB)

    VLF signals from 10 to 30 kHz play an important role in long-range time dissemination, communications, and navigation. A brief history of VLF transmissions is given with particular emphasis on the time dissemination capabilities of the Omega navigational system. Traditional methods are compared with modern capabilities. Traditional lead-edge time dissemination by VLF normally can provide an accura... View full abstract»

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  • Time synchronization via lunar radar

    Publication Year: 1972, Page(s):552 - 557
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (577 KB)

    The advent of round-trip radar measurements has permitted the determination of the ranges to the nearby planets with greater precision than was previously possible. When the distances to the planets are known with high precision, the propagation delay for electromagnetic waves reflected by the planets may be calculated and used to synchronize remotely located clocks. Details basic to the operation... View full abstract»

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  • The role of time/frequency in navy navigation satellites

    Publication Year: 1972, Page(s):557 - 563
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1070 KB)

    This paper discusses the role of time and frequency in three areas: 2) the operational Navy Navigation Satellite System, NNSS; 2) an experimental low-altitude navigation concept termed TIMATION; 3) proposals for advanced navigation satellites. These operating, experimental, and proposed systems all use concepts which allow the user to remain passive. The operational NNSS system uses the Doppler te... View full abstract»

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  • The role of time-frequency in satellite position determination systems

    Publication Year: 1972, Page(s):564 - 571
    Cited by:  Papers (4)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2056 KB)

    Many present-day radio navigation satellite systems employ the use or measurement of time or frequency to provide a position fix for the user vehicle. For example, the position fix obtained by the U. S. Navy's Navigation Satellite Systems (Transit) is based on the precise measurement of the Doppler shift from a single satellite observed by the user vehicle, plus the satellite's orbital elements an... View full abstract»

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  • Airborne collision avoidance and other applications of time/frequency

    Publication Year: 1972, Page(s):572 - 579
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1750 KB)

    Time/frequency technology provides a reliable aircraft collision avoidance system (CAS) that can operate in either synchronous or asynchronous modes. Precision time-ordered techniques of CAS provide both range and range-rate measurements in a one-way sense to all aircraft as well as ground stations within range of transmitted microwave signals. The cooperative system utilizes exact frequency refer... View full abstract»

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  • Time/frequency and transportation

    Publication Year: 1972, Page(s):579 - 589
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1420 KB)

    Current and future problems are presented for the land, sea, and air transportation environments that are, or can be, solved using time/frequency technology. Problem areas in transportation encompass vehicle surveillance and location, traffic management, collision avoidance, command and control, communications, navigation, and search and rescue. Time accuracy requirements vary widely from seconds ... View full abstract»

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  • Frequency and time in communications

    Publication Year: 1972, Page(s):589 - 594
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    Modern communications systems make use of sophisticated multiplexing techniques in order to achieve efficient spectrum utilization and thereby realize the maximum number of message channels through a particular transmission medium. Synchronization of transmit/receive carrier (or clock) generators is essential in such systems to avoid distortion; also, close tolerances on the accuracy of carrier an... View full abstract»

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  • Synchronizing and multiplexing in a digital communications network

    Publication Year: 1972, Page(s):594 - 601
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (920 KB)

    A concept of a totally digital communications network is described in which all signals are converted into digital form and remain so as they are multiplexed, switched, and transmitted. To permit time-division techniques for such network processing, and thus realize significant economic advantages, the digital signals must be either generated in synchronism or brought into synchronism. While the s... View full abstract»

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  • Long-baseline radio interferometry with independent frequency standards

    Publication Year: 1972, Page(s):602 - 609
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (909 KB)

    The present stage of development of long-baseline interferometry using independent atomic frequency standards is reviewed. The technique is being applied to precision geodesy and astrometry and shows great promise as a means for the intercomparison of national time scales at the 1-ns error level. This paper discusses the development of radio interferometry and, in particular, the theory and practi... View full abstract»

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  • Timing and geodesy

    Publication Year: 1972, Page(s):610 - 613
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (457 KB)

    Geodetic science (geodesy) is that branch of science concerned with determining the size, shape, and gravitational field of the earth, and precisely mapping its surface features. Astronomic observations provide essential information in the geodetic process. Both the earth-based observing stations and the observed extraterrestrial bodies (stars, planets, natural and artificial earth satellites) are... View full abstract»

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  • Role of infrared frequency synthesis in metrology

    Publication Year: 1972, Page(s):621 - 623
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (662 KB)

    Infrared frequency synthesis (IFS) techniques are briefly surveyed, and some important results are summarized. The recent measurement of the frequency of the methane-stabilized He-Ne laser is significant due to the accurate measurement of the methane wavelength and its fundamental role in metrology. The possibilities of an improved value for the speed of light and of additional applications for fr... View full abstract»

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  • Progress and feasibility for a unified standard for frequency, time, and length

    Publication Year: 1972, Page(s):623 - 625
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (447 KB)

    The recent successful extension of frequency synthesis upward in the infrared to the 88-THz frequency of the very stable methane frequency standard has implications for expanded uses of frequency/time metrology and hence of frequency/time dissemination systems. After further refinements of the infrared frequency synthesis techniques, metrologists will have the opportunity to define a value for the... View full abstract»

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  • Time transfer using near-synchronous reception of optical pulsar signals

    Publication Year: 1972, Page(s):625 - 627
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    The concept of time transfer between two geographically separated locations by using nearly simultaneous reception times from a common transmission has been used very fruitfully, e.g., the TV line-10 time transfer system and Loran-C. Some germane aspects of the concept are discussed and use of a signal from the optical pulsar NP0532 as the common transmitter is considered. Theoretical consideratio... View full abstract»

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  • Frequency standard work in Egypt

    Publication Year: 1972, Page(s):627 - 628
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    The development of the National Physical Laboratory for metrology in Egypt is described. The Frequency Standards Department has been maintaining a cesium frequency standard since 1967. Reception of VLF transmissions is used for phase comparison with good results. Future goals include improving the reliability of the system and reception of Loran-C as well as investigating applications of standard ... View full abstract»

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  • Ruggedized rubidium frequency standard

    Publication Year: 1972, Page(s):628 - 629
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (338 KB)

    A rubidium frequency standard has been designed that is compatible with ruggedized military equipment. Many of the special features and unique characteristics, such as the thermoelectric cooler, are described. View full abstract»

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  • A time code for the omega worldwide navigation system

    Publication Year: 1972, Page(s): 630
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    Time-of-day information could be added to the signals of the Omega worldwide VLF navigation system by means of a digital code. This could be valuable in resetting precision clocks and in monitoring them for malfunction. Also, Omega's worldwide coverage could then provide timing for automatic recording of data, such as geophysical information, in remote locations. View full abstract»

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  • Worldwide synchronization using the TRANSIT satellite system

    Publication Year: 1972, Page(s):630 - 632
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (482 KB)

    American TRANSIT satellites have permitted improvements in the synchronization of satellite control networks. A prototype model for the decoding of time signals has been built and tested in the station of Brétigny Centre National d'Etudes Spatiales (CNES). This system has been introduced in all the networks and as far back as 1969 an initial synchronization project was established. The rms va... View full abstract»

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North Carolina State University