A new high-speed periodic-threshold comparator for use in a Josephson A/D converter

A Josephson comparator based on a nonhysteric one-junction superconducting quantum interference device (SQUID) for use in a periodic-threshold A/D (analog-to-digital) converter is discussed. Simulations show that a 4-bit A/D converter using this comparator could have a sampling rate of >20 GHz with an analog signal bandwidth of >10 GHz. This performance represents a factor-of-greater-than-five improvement over that of other periodic-threshold A/D converters, which are based on two- or three-junction SQUIDs.<
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