| 摘要 |
Subranging techniques using "digital SQUIDs" are used to design systems with large dynamic range, high resolution and large bandwidth. Analog-to-digital converters (ADCs) embodying the invention include a first SQUID based "coarse" resolution circuit and a second SQUID based "fine" resolution circuit to convert an analog input signal into "coarse" and "fine" digital signals for subsequent processing. In one embodiment, an ADC includes circuitry for supplying an analog input signal to an input coil having at least a first inductive section and a second inductive section. A first superconducting quantum interference device (SQUID) is coupled to the first inductive section and a second SQUID is coupled to the second inductive section. The first SQUID is designed to produce "coarse" (large amplitude, low resolution) output signals and the second SQUID is designed to produce "fine" (low amplitude, high resolution) output signals in response to the analog input signals. The output signals of the first SQUID are coupled to a first comparator having an output for producing a first quantized output signal which is coupled back to the input coil. The output signals of the second SQUID are coupled to a second comparator having an output for producing a second quantized output signal which is also coupled back to the input coil. The outputs of the two comparators may then be further processed for producing a digital version of an analog input signal.
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