| 摘要 |
<p>PURPOSE:To drive a magnetic tape correctly up to a retrieving position even though an operator does not store the count value of the retrieving position, by setting the threshold value at about 1/2 maximum count value, subtracting the count value of the memory position from that of the present position to output different control signals based on whether the result of subtraction is larger or smaller than the threshold value and forwarding fast or rewinding a tape in response to said control signals. CONSTITUTION:The threshold value is set at ''5000'' equivalent approximately to 1/2 maximum value (''9999'') that can be counted at a counting part 3. The count values ''0000''-''4999'' are defined as positive numbers; while the count values ''5000''-''9999'' are defined as negative numbers respectively. A comparing part 10 subtracts the count value of a memory part 5 from that of the part 3 and then decides the rewinding or fast forward directions in response to the positive or negative number obtained from said subtraction. In this case, the numbers having minus codes on the basis of said subtraction are counted in the negative direction to exceed the value ''0000''. Therefore the count value of the part 5 is subtracted from the count value obtained by adding ''10000'' to the count value. Then the rewind control signal corresponding to a positive number obtained from the part 10 is fetched from a tape direction deciding part 12.</p> |
