| 摘要 |
PURPOSE:To simplify constitution as much as possible by placing an electronic swtich, interposed between a series feed type connection line between recording and playback head and an erasing head, in a prescribed bias state on the basis of a reference voltage. CONSTITUTION:For example, a transistor (TR)Q1 turns off and TRQ2 turns on in a recording state; and a TRQ3 turns off, and a TRQ4 off. Then, after a recorded signal applied to a recorded signal input terminal REC-1N is held at a prescribed level through an amplifier A2, it and an oscillation output from a bias oscillator OSC are recorded together on a magnetic tape, being superposed, in series to a recording and playback head H1 and an erasing head H2. In the series feed system, a closer side to the recording amplifier of the ooscillation transformer in the OSC is a low-potential side of a high-frequency voltage, so a bias trapping circuit for the parallel feed system is unnecessary. Thus, the constitution is simplified greatly. |
