Title :
AC Josephson voltage standard: progress report
Author :
Hamilton, Clark A. ; Burroughs, Charles J. ; Benz, Samuel P. ; Kinard, Joseph R.
Author_Institution :
Nat. Bur. of Stand. & Technol., Boulder, CO, USA
fDate :
4/1/1997 12:00:00 AM
Abstract :
Progress toward a Josephson voltage standard for fast dc measurements and accurate ac waveform synthesis is described. A superconductor-normal-superconductor (SNS) junction process is used to make 5 mA critical current arrays with up to 32 768 junctions. With rf excitation at 11 GHz these arrays generate milliampere constant-voltage steps. A bias control circuit that provides output current amplification, transient suppression, and submicrosecond settling time is used with both superconductor-insulator-superconductor (SIS) and SNS junction arrays for fast, automated measurements of A/D converter linearity, a test for subnanovolt accuracy, waveform synthesis, and a preliminary measurement of the ac-dc difference of a thermal voltage converter
Keywords :
analogue-digital conversion; measurement standards; superconducting junction devices; superconductor-insulator-superconductor devices; voltage measurement; waveform generators; 11 GHz; 300 mV; 5 mA; A/D converter linearity; AC Josephson voltage standard; ac-dc difference; accurate ac waveform synthesis; bias control circuit; critical current arrays; fast automated measurements; fast dc measurements; milliampere constant-voltage steps; output current amplification; rf excitation; submicrosecond settling; subnanovolt accuracy test; superconductor-insulator-superconductor junction arrays; superconductor-normal-superconductor junction process; thermal voltage converter; transient suppression; Analog-digital conversion; Circuit synthesis; Circuit testing; Critical current; Current measurement; Josephson junctions; Measurement standards; Superconducting devices; Time measurement; Voltage;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
