Intercomparison of thermal converters at NIM, NIST, PTB, SIRI, and VSL from 10 to 100 MHz

Abstract

Coaxial thermal voltage converters have been intercompared among NIM, NIST, PTB, SIRI, and VSL in the frequency range from 10 MHz to 100 MHz. The intercomparisons were made from 1988 through 1990. This paper briefly describes the highly varied methods and underlying principles on which RF-dc difference determinations are based in each laboratory, the transport standards used, and the results of the intercomparisons. The results from the participating laboratories are in very good agreement; therefore, we believe that the determinations of RF-dc difference in this frequency range are very well established.

Evaluation of the calculable high frequency AC-DC standard

“…It clearly shows the large differences between the two models, especially at high frequencies. The calculated difference at 100 MHz, around 3400 V/V, is of the same order as was found during the intercomparison of thermal converters at high frequencies [3]. The connecting copper wire at the input (c1) and the feedthrough lead between the range resistor and TE (c2) are mainly responsible for the shift in the ac-dc transfer difference, about 25% and 60%, respectively.…”

“…However, an intercomparison with other institutes [3] has indicated potential discrepancies for the ac-dc transfer in the upper frequency range. Also, one of the fabricated standards (EUR-18) gives unexpectedly large deviations between the model and the measurements at high frequencies.…”

Evaluation of a Calorimetric Thermal Voltage Converter for RF–DC Difference up to 1 GHz

“…During the calibrations, the RF-DC transfer difference δ N of the reference standard NRV-Z51 at its type-N input connector is determined in terms of its calibration factor and the voltage reflection coefficients using (11). δ N is then transferred to the middle of the built-in internal tee using (15), and later works as δ Std in (2).…”

“…At the National Research Council of Canada (NRC), the realization of such a standard is a calorimetric thermal voltage converter (CTVC) [4], [5], which is different from other commonly used standards such as an assembly of a calculable coaxial resistor and a single-junction thermal converter [1], [3], a coaxial calorimeter, a bolometric bridge [2], or a planar multijunction thermal converter (MJTC) on a quartz crystal chip [6], [7].…”

CCE intercomparison of AC-DC voltage transfer standards at high frequencies (1-50 MHz)

“…There had never been an extensive CCE intercomparison, only an (informal) intercomparison between six laboratories has been carried out [9]. In the meantime, the CCE has pointed out this type of intercomparison as one of the key comparisons.…”