| 摘要 |
PURPOSE:To perform recording satisfactorily and to prevent unrequired cross modulation from being generated by providing two or more mean values of a recording circuit to be supplied to a rotary magnetic head, permitting a large magnitude of recording current to flow for a prescribed time from starting recording, and a small magnitude of recording current after the lapse of the prescribed time. CONSTITUTION:FM modulation signals S3 and S4 are inputted from terminals 19 and 20 to the magnetic heads 2 and 3 and a driving circuit which supplies the recording current to the magnetic heads. The signals S3 and S4 are adjusted to the optimum levels by variable resistors 12 and 13, then, become FM modulation signals S5 and S6. The signals S5 and S6 are inputted to the bases of transistors 8 and 9, respectively, and are current-amplified, then, become signals S7 and S8, and are inputted to a recording amplifier R6 and a recording amplifier L7, then, become signals S9 and S10 which hold currents sufficient for the magnetic recording of the recording heads 2 and 3, and are outputted from the recording amplifiers. A part consisting of resistors 14 and 15 and field effect transistors 16 and 17 is a circuit to vary a current value stepwise, and an SI signal is inputted from a terminal 18 to a control circuit 1. |
