The infrared thermal converter as a highly precise transfer standard

The new thermal converter developed has the following AC-DC transfer errors: lower than 2.5/spl middot/10/sup -4/ ppm (1 /spl sigma/) at frequencies from DC to 75 kHz; equal to: 10/sup -3/ ppm 100 kHz and to 0.01 ppm at 125 kHz. The design is based on an infrared thermal sensor irradiated by a "flat strap sandwich heater resistor" (FSSHR). The high accuracy results qualify the converter as a possible AC-DC reference transfer standard.