| 摘要 |
PURPOSE:To adjust switching timing of a rotary head automatically by comparing saw-tooth waveform level having wave height corresponding to rotation speed of the rotary head and waveform level obtained by sample holding the peak value of the waveform and voltage dividing the hold output according to the number of rotary head. CONSTITUTION:Output side of a saw-tooth wave generating circuit 10 is connected to an inversional terminal of a comparator 13. The comparator 13 makes voltage divided output of a voltage dividing circuit 12 reference input and makes saw-tooth wave output of the saw-tooth wave generating circuit 10 comparative input, and compares the two inputs. A head switching signal forming circuit 8 switches to the first rotary head H1 side at timing by which output of high level is given from the comparator 13, and forms the first head switching signal that enables driving of the first rotary head during continuation of output of the high level. Further, it switches to the second rotary head H2 side at timing by which output of low level is given, and forms the second head switching signal that enables driving of the second rotary head H2 during continuation of the low level output. |
