| 摘要 |
An addressing method permits the synchronized reproduction of digitized information recorded on different tapes in different formats, each of which uses a different number of data tracks for each channel of analog information. A first tape uses one track per analog channel. On a second tape each channel is recorded simultaneously in four tracks at one-fourth of the recording speed of the first tape. The data on both tapes is arranged in data blocks that occupy same amount of space. Both tapes have sector intervals occupying a space corresponding to four data blocks, and each sector interval has an associated sector address. On the first tape, the sector addresses in successive intervals are incremented by one, while on the second tape the successive sector addresses are incremented by four. Thus, the data on both tapes can be reproduced in synchronization at their respective recording speeds by maintaining the difference between the sector addresses on the two tapes constant. An apparatus for maintaining synchronized reproduction of two such tapes uses two tape recorders, each of which provides the sector addresses reproduced from the tapes to a subtraction circuit. The digital output of the subtraction circuit represents, in both sense and magnitude, the extent to which synchronization of the playback of the tapes has been lost. A digital-to-analog converter converts the subtraction circuit output into an error signal for controlling the speed of one of the tape recorders.
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