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Accreditation of RF Measurement, IEE Colloquium on

Date 2 Feb 1993

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Displaying Results 1 - 9 of 9
  • Customer requirements for electrical calibrations

    Publication Year: 1993 , Page(s): 3/1 - 3/2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    The author attempts to explore the different requirements placed upon calibration laboratories by their customers. In addition the limitations imposed by the accreditation bodies and their subsequent implications are discussed View full abstract»

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  • Guidance on the use of coaxial connectors in radio frequency and microwave circuits

    Publication Year: 1993 , Page(s): 8/1 - 8/4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    The author suggests that coaxial connectors are often the most mistreated and ignored part of a measurement system. NAMAS have produced a coaxial connector guidance publication number NIS4303 to give information to NAMAS Accredited Laboratories on the care and use of the most commonly encountered connector types View full abstract»

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  • A method for assessing the magnitude uncertainties associated with network analyser measurements

    Publication Year: 1993 , Page(s): 7/1 - 7/7
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (236 KB)  

    Without correction, errors present within an automatic network analyser (ANA) will significantly affect the response of a measurement, resulting in a misleading representation of the parameter measured. By calibration (i.e. applying error correction), these affects can be significantly reduced which results in a large overall improvement in accuracy. Calibration is the use of known impedance standards that are defined electrically, or physically. These impedance standards are measured by the ANA and used in the appropriate error correction model. After calibration the device under test (DUT) is measured. The error model of the ANA as defined by the standards mathematically relates the raw measurements of the DUT, to produce a corrected measurement. The accuracy to which the standards are known dictates how well systematic errors can be eliminated. Under these conditions some residual systematic errors will remain. The author discusses the effects of the residual errors upon the measurement and demonstrates how well they can be determined View full abstract»

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  • Traceability-the national roles

    Publication Year: 1993 , Page(s): 2/1 - 2/4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    Traceability is defined as a process whereby a measurement is compared to national standards by an unbroken chain of comparisons. The author discusses a traceability hierarchy in the UK which puts the industrial base as being supported by a number of calibration laboratories which in turn are supported by a standards laboratory. The traceability hierarchy has within it the Services Electric Standards Centre (SESC) which has a role as the Master Reference Laboratory and as such acts as a major interface between the standards laboratory and the other NAMAS Accredited Laboratories. The SESC has a long history of RF and microwave metrological work and has made a significant contribution to the expertise in this field. The other feature of the traceability hierarchy in the UK since 1967 is the National Measurement Accreditation Service (NAMAS) (formerly British Calibration Service) whose role is that of assessing all of the technical aspects of a laboratory's practices in regard to accreditation for specific tests or calibrations View full abstract»

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  • RF power-review of current techniques for power sensor calibration

    Publication Year: 1993 , Page(s): 5/1 - 510
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    The traceability for RF power measurements in the range 100 kHz to 26.5 GHz is normally achieved by NAMAS accredited laboratories using thermocouple power sensor calibrated by SESC. This system has given adequate uncertainties over the past fifteen years. There is an increasing requirement for the upper frequency limit to be extended and for some sensors to be calibrated with lower uncertainties. Techniques that minimise the mismatch uncertainty could be introduced in commercial laboratories NPL have the capability to extend the frequency range and can provide lower uncertainties for the Reference Standard sensors. These measures should be sufficient to keep pace with industry requirements View full abstract»

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  • Modulation: fundamental techniques for traceability

    Publication Year: 1993 , Page(s): 6/1 - 6/6
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    Basic methods used to measure amplitude modulation are discussed. These include: oscilloscope slideback method; spectrum analyser method; analogue switch method; and Bessel-zero method View full abstract»

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  • Accreditation of r.f. measurements: the future

    Publication Year: 1993 , Page(s): 9/1 - 9/2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    In the field of electromagnetic compatibility (EMC) testing, including r.f. testing, approximately 30 NAMAS-accredited laboratories exist in 1993. These numbers reflect the business realities of demand for, and cost of, providing accredited services, whether in-house to support other business functions, or offered to a wider market. Many r.f. measurements are relatively difficult to perform reliably, exacerbated by the interdependence of various measurement parameters, such as attenuation, impedance, power, and voltage standing wave ratio, and increasing use of complex instruments such as the automatic network analyser. The known difficulties should be a motivation to seek assurance of measurement competence, and this alone should be a clear influence on growth of accredited r.f. measurements. A number of other factors which are likely to extend the need for, and the technical range of, accreditation in the r.f. field, are discussed View full abstract»

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  • The status of NAMAS accreditation for electrical calibration laboratories

    Publication Year: 1993 , Page(s): 1/1 - 113
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    RF measurement accreditation is essential for providing acceptable traceability to UK industry, and it is therefore very important that the country has sufficient accredited laboratories to provide this facility. With the limited number of NAMAS laboratories accredited for RF measurements, it would be in the interests of companies within the UK to further this network to ensure that full calibrations are undertaken for RF instrumentation. The objective of the author is to promote greater interest in the subject of RF measurement accreditation and to explore techniques by which accreditation can be achieved in the most expedient and cost-effective manner View full abstract»

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  • Calibration of signal generators

    Publication Year: 1993 , Page(s): 4/1 - 4/6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    There are a number of different measurement parameters in the field of radio frequency calibration. In order to provide a comprehensive measurement capability, the RF calibration laboratory must have the equipment and expertise to deal with these parameters over a suitable range and with sufficient accuracy. Amongst the most commonly encountered items submitted for calibration to the RF laboratory is the general purpose signal generator. Such instruments embody most of the commonly encountered parameters in RF measurements and therefore a study of a typical signal generator specification is a useful means of determining the measurement capability requirements for a typical RF laboratory View full abstract»

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