| 摘要 |
795,057. Electric digital-data-storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Oct. 4,1954 [Oct. 7, 1953], No. 28496/54. Class 106 (1). In a method and an apparatus for the storage and recovery of information employing the spinecho or free nuclear induction technique (described in two articles by E. L. Hahn in the " Physical Review," November 15, 1950 (page 580) and in " Physics Today," November 1953 (page 5), respectively, both of which articles are referred to) the inhomogeneity of the magnetic polarizing field is varied to thereby reduce the power requirements. According to the spinecho technique if a sample 10 (water), Fig. 1, is placed in a constant inhomogeneous magnetic polarizing field and if two pulses of R.F. current (30 mc/s.), an information pulse. Fig. 3, and a recollection pulse at a time T1 after the information pulse, are passed through a coil 11 surrounding the sample, then at a time T2, where T2 = T1, after the recollection pulse an echo signal is induced in the coil 11. When several information pulses P1, P2, P3, Fig. 5, are applied to the sample, several echos S1, S2, S3 are produced, each echo being the " mirror image " of its information pulse in the recollection pulse. According to the invention the practical application of this technique to the storage and recovery of information is made possible by varying the inhomogeneity of the magnetic polarizing field by D.C. coils 13, 14, Fig. 1, in such a way that the sample is subjected to a very distorted field, Fig. 6B, at all times except during a recollection pulse during which the coils 13, 14 are not energized and the inhomogeneity is reduced to that due to the magnet 12 only. |
