| 摘要 |
PURPOSE:To detect the tape speed at the recording time digitally, when the tape where the signal is recorded in three kinds of speed is reproduced. CONSTITUTION:In the recorded reproducing control signal, frequencies different by respective reproducing modes within the range of 10Hz-90Hz are obtained. If this signal is recorded in the two-hour (2H) mode and is reproduced in another reproducing mode, the reproducing control signal of 15Hz or less is obtained, and output na of counting circuit 8 becomes low, and pulse outputs are generated in na and nc. Outputs (a) and (b) of R-S.FFs 9 and 10 are held in L:L to detect the 2H recording mode. If the signal is recorded in the six-four (6H) mode and is reproduced in another reproducing mode, the reproducing control signal of 45Hz or more is obtained, and nb and nc become low, and outputs (a) and (b) are held in H:L to detect the 6H recording mode. If the signal recorded in the four-hour (4H) mode is reproduced in another reproducing mode, outputs (a) and (b) become H:L to detect the 4H mode. |
