| 摘要 |
987,357. Automatic position control. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 18,1963 [Nov. 30,1962(2);Dec. 18,1962],No. 45363/63. Heading G3R. [Also in Divisions G5 and H1] A memory system comprises: a magnetic recording medium 11, Fig. 6 having a non-magnetic substrate and first and second magnetisable layers on which may be recorded data signals and servo signals;a transducer 10 for sensing the servo signals and for sensing and/or recording the data signals;and a servo system to effect relative movement between the medium and the transducer to bring the transducer to a predetermined position relative to the location of the servo signals,for sensing or recording the data signals. As described, servo signals of frequency F1 or F2 are recorded on the lower, high coercivity, layer on a number of concentric tracks, alternative tracks being the same frequency. The data signals are recorded on the upper, lower coercivity, layer, their tracks being spaced between those of the servo signal, Fig. 5. The output from the sensing coil 15 of transducer 10 is fed via a wide band amplifier 14 to filter amplifiers 16,17,18 which separate the data signal and the two servo signals. The two servo signals are then fed via gates 19, 20 to produce a control signal which positions the transducer 10 mid-way between two of the servo tracks. The gates 19, 20 are controlled by an address register 13 which determines which of the two frequencies F1, F2 is passed by the gates. If the transducer 10 is over an "odd" data track, then frequency F1 passes through gate 19 and F2 through gate 20. If on the other hand it is over an "even" track, F1 passes through gate 20 and F2 through gate 19. |
