Operation of a 64-bit superconducting shift register at 8 GHz

A 64 b superconducting shift register based on edge-triggered gates has been tested up to 8.45 GHz with two-phase sine wave clocks. The edge-triggered gates are made by serial connection of a Josephson junction and a modified variable threshold gate, fabricated by an Nb-AlO/sub x/-Nb process. Wide operating margins and simple two-phase clocks make this shift register relatively easy to test. Power dissipation is 10 mu W/b.<
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