Calibrating RF Test & Measurement Equipment
esz AG's radio frequency laboratory is designated to be one of Europe's best equiped radio frequency calibration laboratory and characterized with measurement capabilities up to 67 GHz. The RF-laboratory features redundant system comparison by cross referencing the radio time signal carrier frequency (DCF-77) against a GPS-signal resulting in measurement uncertainties of below 5 parts per trillion.The RF-Laboratory is equipped with state-of-the-art power analyzers, frequency, power of different connector systems enabling esz AG to be highly responsive.
**Down to the 5th of a trillion: Calibration up to 67 GHz **
Deploying at hand reference standards including the corresponding coaxial systems, multi-purpose working standards for telecommunications, communications engineering, avioncs, transmission measuremts or RF test and measurement equipment is traced and calibrated at the most precise and accurate level. The installed test procedures comply with internationally recongnized techniques and are similar to methods applied at any leading calibration laboratory. Since 2004 most of esz AG's RF measurement quantities are accredited by the German accreditation body (DAkkS).
To calibrate RF power, a symmetrical power splitter will acquire incident power (in a multiple step approach) and be compared to results taken from a test object. Verification of frequency and linearity (power probes and power analyzers) require up to 8 measuring cycles in different axial, rotating positions and per frequency. Inbetween cycles, typically four, reference probe and device under test are physically disconnected from and reconnected to a different power splitter output, or a second calibrated power standard whilst realizing yet another axial rotation. Rotation is required as part of the evaluation process in order to determine whether one of the connectors appears to be defective: Simply due to the fact that the occuring standard deviation inbetween cycles, as found, is extremely high.
RF-Power calibration over 20 decades
Evaluating reflection factors and attenuation at frequency ranges from 9 kHz to 67 GHz is realized using vector network analyzers. Calibration kits for most common 50 O and 75 O-plug connectors are available. Completing 1-Gate (respectively 2-Gate) calibration the complex reflection factor Gamma, attenuation or complex scattering coefficient in terms of absolute value and phase is subject to identification. Air lines of various length and defined mismatches are used to establish traceability and primary reference. The latter are applied to monitor the systems accuracy, assess residual error and measurement uncertainties. Calculation of measurement uncertatinties is in accordance with EA-10/12 and reflect the actual system data. The relevant standard equation for detemination of reflection factors addresses unknown phases and complex values in accordance with the identified system correction values and are subject to periodic comparison to all taken results and verification measurements.
Scattering coefficients-calibration: Attenuation and reflection factor
Die Messung von Reflexionsfaktoren und Dämpfung im Frequenzbereich von 9 kHz bis 67 GHz wird an vektoriellen Netzwerk-Analysatoren durchgeführt. Hierfür stehen Kalibriersätze für die meisten koaxialen 50 Ω und 75 Ω-Steckersysteme zur Verfügung. Nach vollständiger 1-Tor- (bzw. 2-Tor-) Kalibrierung ermöglichen die Geräte die Bestimmung des komplexen Reflexionsfaktors Gamma, der Dämpfung oder der komplexen Streuparameter eines Prüflings nach Betrag und Phase. Als Rückführungs- und Bezugsnormale stehen Luftleitungen unterschiedlicher Länge, Abschlüsse und Fehlabschlüsse für die Steckertypen zur Verfügung. Mit diesen werden die Systemgenauigkeit nach durchgeführter Kalibrierung überprüft, die zu erwartenden Restfehlergrößen und die Messunsicherheiten abgeschätzt. Die Berechnung der Messunsicherheit nach einer Kalibrierung erfolgt gemäß der Publikation EA-10/12 anhand der effektiven Systemdaten. Die maßgebliche Modellgleichung für die Messung des Reflexionsfaktors wird darin für komplexe Größen unbekannter Phase formuliert und mit den Datensätzen der Einkalibrierung (Systemfehlerkorrektur) ausgewertet und mit den Ergebnissen der Verifikationsmessungen regelmäßig verglichen.
Laboratory conditions and short-term stability below 0,5 Kelvin
The calibration system for attenuators at considerably high attenuation is determined a direct measuring technique in the means of measuring signal generator’s and signal receiver's utilizing selective measuring systems. The environmental temperature impact is kept below 0,5 K realizing contemporary reference measuring and test object implementation. Tracing RF-attenuation requires directly traceable calibration standards in terms of attenuators (for details refer to EA-10/12). Single attenuators cover a great deal of the required dynamic range. The latter with respect to traceability are to be extended applying designated working standards.
Calibrating RF auxilliary measurement quantities
Beeing the initiator to calibration guideline DKD-L 02/1 esz AG consider themselves significantly involved in the developement of documents and guidelines to simplify and clearify the calibration, handling, traceablity and accreditation of so called "RF auxilliary measurement quantities". The initiative aimed at including measurement quantities like display linearity, IF gain, bandwidth, filter form factor, filter selectivity, modulation or displayed average noise level (DANL) within accredited calibration reports, in accordance to comply with common procedures for ISO calibration reports. The gap left behind by non-consideration with respect to metrological traceability is finally being closed by defining and classifying RF auxilliary measurement quantities. All test results for complex test objects e.g. receivers, spectrum analyzers or signal generators are officially considered and documented as part of accredited calibration reports and available to partner laboratories and customers.
Active participation in developing guidelines and committee activity for clear requirements
esz AG is taking an active role in the continuous development of guidelines as being an active member of the technical committee VDI GMA 3.12 for electrical measurement quantities. esz AG consider themselves as the industrial voice transporting the industrie's requirements and actively shaping calibration procedures and measurement uncertainties.
Calibrating EMC Test & Measurement Equipment
Testing, evaualuation und verfiying electromagnetic compliance for electronic equipment as part of the CE-certification process falls to the original equipment manufacturer, their EMC-test-houses or third party EMC-laboratories. Thus, engineering standards such as IEC, CENELEC and CISPR are determined are increasingly important within competetive, global markets.
The latest normative standards and publications are always available and considered to calibrate EMC-testing equipment
To document a system's or test object's responsitivity to voltage, electric current, mains-borne or radiated disturbance are subject to evaluation using state-of-the-art EMC-testing equipment. The latter characteristics are outspokenly important as the sole source for reference and are unevadable tied to calibration and documentation. The quintessence, for leading EMC-testing laboratories, is traceable, compliant DIN EN ISO/ IEC 17025 calibration. esz AG's calibration laboratories calibration refers to the latest norms, standards, publications and guidelines regarding EMC test and measurement equipment such as burst generators, surge generators, EMC probes, EMC fixtures and auxiliary EMC test and measurement equipment. esz AG's capabilities in terms of calibration include system verification, accredited and compliant calibration for test and measurement equipment in accordance to:
- Electrical disturbance generators (DIN EN 55022 bzw. 55014 / 55011)
- Harmonics (DIN EN 61000-3-2 bzw. DIN EN 61000-4-7)
- ESD compliance (DIN EN 61000-4-2)
- Burst (DIN EN 61000-4-4)
- Surge (DIN EN 61000-4-5)
- RF-electromagnetic or induced (DIN EN 61000-4-3 respectively DIN EN 61000-4-6)
- Dips / Interruptions (DIN EN 61000-4-11) or
- Flicker (EN 61000-4-15)
esz AG's filed RF-calibration is specialized in calibration for RF- or RF related test and measurement equipment as follows:
RF-power meters / RF-signal generator / spectrum analyzers / attenuators / RF receivers / radio test systems / frequency counters / EMC test equipment / coupling networks / line impedances / RF filter / RF components