Application of Josephson series arrays to a DC quantum voltmeter

Josephson series arrays with a binary sequence of nonhysteretic superconduc tor-insulator-normal metal-insulator-superconductor (SINIS) junctions have been realized. The arrays of up to 8192 junctions (14 bits) are operated at microwave frequencies of about 70 GHz with low microwave power, An electro nic system was built to drive an automated de quantum voltmeter. Two electr ically isolated quantum voltmeters (QVMs) in the same cryoprobe and driven by one frequency have been used for calibrating resistive dividers with the intention of demonstrating some advantages of these instruments.