A high-speed analog-to-digital converter using Josephson self-gating-AND comparators

A Josephson Analog-to-Digital (A/D) converter which employs Self-Gating-AND (SGA) circuits as comparators has been designed and experimentally investigated. A functional description of the SGA is presented and the design of a four-bit A/D converter is described. High-speed measurements demonstrate four-bit quantization of 280 MHz sinusiodal inputs, and three-bit quantization of 499 MHz inputs at a 1.0 GHz conversion rate.