| 摘要 |
1498860 Superconductive circuits INTERNATIONAL BUSINESS MACHINES CORP 24 Nov 1975 [23 Dec 1974] 48152/75 Heading H3X In a superconductive multi-OR logic circuit comprising a plurality of logic gates XI-XN connected in series between a gate current generator 21 and an output sensing line 26 controlling a Josephson tunnelling device J SENSE, the charge of current in the output sensing line in response to a logic input is enhanced by a sensing circuit comprising a further Josephson device Jl and an inductor L1 connected in series with the output sensing line 26, the series combination 20 being shunted by an inductor L2 of higher value. As shown each logic gate comprises a pair of Josephson devices, but a single such device for each gate may be used if ground plane connections are provided. The logic circuit is operated by three phase pulses # 1 , # 2 , # 3 . In the first "set up" phase # 1 , Josephson device Jl is switched to its finite voltage state by control current in a line 24 and the gate current I 0 from generator 21 is directed wholly through inductor L2. Device J then relapses to its zero voltage state but the diverted current continues to pass through the shunt inductor. In the second "data in" phase # 2 a change of gate current I 0 is produced if a logic input is applied in this period, this change being almost wholly passed through the series circuit path 20 as a negative current. Gate current is applied at this time to Josephson device J SENSE, and if current is present in the series path 20 the device is switched to its finite voltage state to provide an appropriate output. In the third "reset" phase # 3 control current is again applied to device J1 which switches to its voltage state to extinguish any circulating current in the sensing circuit. At the same time the gate current I 0 ceases and any switched logic gate is reset.
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