| 摘要 |
PURPOSE:To hold the counted value of a counter and the run position of a magnetic tape in specified relation even when the magnetic tape runs forward and backward, by calculating differences of pulses obtained according to the turning direction of a rotating body. CONSTITUTION:Rectangular pulses, etc., generated according to the rotation of a rotating body 10 which turns clockwise and counterclockwise are counted 19. In this case, the rise or fall edges of a rectangular pulse, etc., generated when the body 10 turns clockwise is detected 16, and the rise or fall edges of a rectangular pulse, etc., generated when the body 10 turns counter clockwise is detected 17. Said detected 16 and 17 pulses are counted by the counter to obtain counted values, and the difference between the counted values is calculated 19 to supply the calculation result to a display device 20. |
