| 摘要 |
1,132,176. Magnetic records. SIEMAG FEINMECHANISCHE WERKE G.m.b.H. 3 March, 1967 [26 April, 1966], No. 10126/67. Headings G4C and G4M. Binary-coded characters having an even number of bits, e.g. 4, are recorded on magnetic tape or a magnetic strip on a ledger card in a manner which allows errors caused by incorrect positioning of the recorded bits to be detected. There are half as many information tracks I as there are bits in the characters, i.e. for 4 bits there are two tracks I 1 , I 2 on which bits are recorded in NRZ form, and there is the same number of complement tracks K 1 , K 2 . Each track is subdivided into alternating bit areas S 1 , S 2 , even-numbered bits being recorded in S 1 areas, and odd-numbered bits being recorded in S 2 areas. Each track I has the same polarity as its associated complement track K in areas S 2 and the opposite polarity to the complement track K in areas S 1 , and any displacement, either lateral or longitudinal, of a recorded 1 bit into an adjacent bit area causes this relationship to be reversed, so that such errors can be detected when the record is sensed, e.g. by heads moving relatively thereto. |
