| 摘要 |
PURPOSE:To decide the optimum writing current value from both count values, by detecting and counting the dropout of waveforms recorded at the writing time and at the same time, detecting phase deviation of the recorded waveforms and counting error signals whose phases are deviated beyond a fixed level. CONSTITUTION:Writing is performed on a magnetic tape with the writing current value of a nonvolatile RAM2. After writing, waveforms read out from a reading head (RH) are sent to an amplitude detecting circuit 5 where the dropout of waveform data is detected and counted. The clock of a VFO6 and read data are compared with each other in phase in a phase deviation detecting circuit 7 and, when the phase deviation exceeds a fixed value, a phase error signal and count value are outputted. A writing current deciding circuit 33 decides whether or not a writing current is appropriate from both the count values and, when the writing current is improper, sets a proper writing current and rewrites the writing current value in the nonvolatile RAM2. |
