| 摘要 |
PURPOSE:To detect the code errors with the same processing even in case the signal time series of a reproduction mode is equal or reverse to that of a record mode, by adding a direction detecting circuit means and an addition circuit which defines 2 as a divisor to a conventional error detector using CRC codes. CONSTITUTION:A direction signal detecting means 11 and an addition means 14 which defines 2 as a divisor are provided in addition to a conventional synchronizing signal detecting means 12, a control signal generating means 13 and a CRC error detecting means 15. The means 11 first discriminates whether a magnetic tape is set under a forward or reverse reproduction state. While the means 12 detects the cycle of data contained in the reproduction signal. The desired control signal is produced by the means 13 and the divisor '2' is added to the desired area of the reproduction signal by the means 14. Then the detection of errors is possible despite the reproduction signal set under a forward ore reverse reproduction state by means of the means 15 which is capable of division by a produced polynomial or its reverse polynomial and also can set all internal shift registers at '0' or '1' before calculation.
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