| 摘要 |
1,205,206. Non-return-to-zero magnetic recording system. HONEYWELL Inc. 31 March, 1969 [16 April, 1968], No. 16793/69. Heading G4C. [Also in Division H3] A NRZ recording system is characterized in that between adjacent blocks of data, referred to as " records," the recording current is allowed to return to zero and in that it is reduced to zero relatively slowly-compared with the normal transitions-so that only a very small (less than 3% of the normal) signal is produced during reading. A seven-track tape recorder is described, Fig. 1, successive input words being registered 25 to control the write heads 12 in the usual way. A parity bit produced 28 for each track, is recorded at the end of each record, which ensures that the final current in each head is always in the same direction and then when a write control signal ceases the recording head current produced under the control of register 25 is cut-off but it is immediately replaced by current from a ramp-generator and progressively reduced to zero. A transistor circuit (Fig. 3, not shown) see Division H3, showing how a ramp generator can be switched into operation to control the head current at the end of a record, is described. |
