| 摘要 |
<p>861,282. Electric selective signalling systems. INTERNATIONAL BUSINESS MACHINES CORPORATION. April 13, 1959 [April 11, 1958], No. 12416/59. Class 40 (1). [Also in Group XXXVI] An analogue to digital converter comprises a closed loop of material capable of exhibiting super conductivity, said loop including a hard super conductor 4, Fig. 1, and a soft super conductor 6, magnetic field producing input means 16 inductively coupled to said hard super conductor and output means 12 arranged to give an indication upon each change of state of said soft super conductor. When certain materials are cooled to very low temperatures (e.g. by immersion in liquid helium) they become super conductive, that is their electrical resistance becomes substantially zero. If a magnetic field of sufficient magnitude is applied to a super conductor it becomes normally conductive (that is its normal resistance returns). Some substances such as bismuth-lead eutectic require a large magnetic field before this occurs and are referred to as " hard " super conductors whereas others, such as lead-indium alloy, require a relatively low field and are referred to as " soft " super conductors. In the circuit described, if a varying current, Fig. 2, is passed through input coil 16, for each incremental change in the current by an amount Ic an output pulse OA, OB, &c. is said to be produced in coil 12 and applied to an amplifier 14. The Specification contains a statement as to the principle by which the circuit is thought to function. Specification 861,280 is referred to.</p> |
