| 摘要 |
PURPOSE:To attain accurate counting of a magnetic tape running amount easily with a simple constitution, by detecting a time required for constant rotation after detecting the time required for constant rotation of either one of reels, and repeating the operation. CONSTITUTION:A constant rotating time detection circuit 6 detects the time required for a prescribed rotation of a supply reel 2a based on an output signal of a photo sensor 4 in response to a start signal (c) to count the amount of running of a magnetic tape 1 or an instruction signal (f) from a control circuit 8. A constant rotating time detection circuit 7 detects the time required for a constant rotation of a winding reel 3a based on an output signal of a photo sensor 5 in response to an instruction signal (d) of the circuit 6. The control circuit 8 responds to a count instruction signal (e) from the circuit 7, counts the amount of running of the magnetic tape based on a direction of rotation signal (g) representing the running direction of the tape 1 and displays it on a display 9. |
