| 摘要 |
Binary data is stored on a moving magnetic medium as data transitions occurring at multiples of a nominal time interval and pairs of control transitions are recorded on the medium between successive data transitions whenever data transitions occur at some given multiple of the nominal time interval that is larger than one. The time interval between the pair of control transitions is substantially smaller than the nominal time interval. Variations in the speed of the medium during recording are sensed and the time of occurrence of the pair of control transitions is adjusted as the speed of the medium varies to maintain a predetermined spacing relative to the successive data transitions between which the pair of control transitions is recorded. An oscillator synchronized to a multiple of the frequency of occurrence of clock transitions on the medium and a counter responsive to the oscillator are employed both to retrieve and to store data. During retrieval, the states of the counter provide a group of successive strobe pulses, the sum of the durations of which remain equal to the period between clock transitions as the speed of the medium varies. During storage, the data and control transitions are recorded on the medium responsive to selected states of the counter to maintain the predetermined spacing between data and control transitions as the speed of the medium varies.
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