GB870825A - A method of and means for magnetic tape recording - Google Patents

Abstract

870,825. Digital data-storage apparatus. NYMAN, B. C. G. Nov. 26, 1958 [Nov. 27, 1957; Jan. 31, 1958], No. 38169/58. Class 106 (1). A method of preparing an error-free magnetic tape comprises the measures of recording impulses representative of digital data while the tape is at rest between the steps of a step-bystep feed, recording spacing impulses and where necessary erratum impulses, the tape being then .played back in reverse whereby a copy may be made, the erratum signals disabling the recording mechanism until the next spacing signal is detected. Data recordings are shown at 9-11, 13, 14 and 16 in Fig. 2 with spacing recordings 12 and an erratum recording 15. Fig. 3 shows the error-free copy with blank positions in place of spacing and faulty recordings. A revertive impulse counter is coupled either to the primary recording apparatus or to the copying device. Assuming the former case, depression of a key 32 actuates a set of contacts to send a pulse to appropriate recording-heads 24, to charge a condenser 36, and to energize a driving magnet 31. When the key is released relapse of magnet 31 advances the tape and condenser 36 is discharged to close switch 29. As the tape moves the recorded signal generates an impulse in magnet head 24, which impulse is amplified at 30 and passed to an indicator. If recording fails to take place, the feed-back impulse fails to appear and an alarm circuit is closed or a relay 40 is energized to lock the keyboard.