RF-DC Transfer Difference Standards and Calibrations at NRC
RF-DC Transfer Difference Standards and Calibrations at NRC
Piotr S. Filipski, Institute for National Measurement Standards, National Research Council
At the National Research Council of Canada (NRC) the primary standard of AC-DC transfer difference at frequencies from 10 kHz to 100 MHz is a Calorimetric Thermal Voltage Converter (CTVC.) Because of a simple design, not unlike a coaxial calorimeter for RF power measurements, its frequency characteristic can be estimated theoretically from a number of mechanical and electrical parameters. An internal Tee, integrated into the CTVC, improves calibration accuracy of working standards.

Over the years several of these converters have been manufactured for different operating voltages and with different frequency characteristics, leading to an optimized design with a frequency characteristic practically flat over eight decades of frequency.

The paper describes details of construction of the CTVC. Results of RF-DC transfer difference measurements and uncertainty evaluation of the converter are discussed together with construction and operation of a semi-automatic RF-DC Transfer Comparator used for these measurements.