Synthesis of precision waveforms using a SINIS Josephson junction array

A synthesizer of precision ac waveforms based on a binary superconductor insulator-normal metal-insulator-superconductor (SINIS) Josephson junction array has been developed. The array segments are individually biased using a high-speed bias source which gives a switching time of approximately 250 ns between voltage steps. The accuracy limitations of the system due to limited risetime and bandwidth are discussed. Comparisons between the synthesizer and a planar multijunction thermal converter (PMJTC) indicate that it is possible to synthesize sine waves with known rms value having an accuracy in the range of 1 part in 10⁷.