| 摘要 |
PURPOSE:To reduce a power loss and also to miniaturize a recorder by applying a switching regulator type to a motor driving amplifier and by connecting a power battery direct to a motor in rapid traverse, rewind and motor start modes. CONSTITUTION:Once supplied with rapid traverse command FF and rewind command REW, selector circuit 8 selects battery power voltage +B and applies it across drum motor M. In recording and reproduction modes, on the other hand, detector 7 outputs reference rotation-frequency detection signal RD, when motor M reaches a reference rotational frequency, and circuit 8 selects and applies the output of switching regulator type motor driving amplifier 6' across motor M. In this case, amplifier 6' develops a direct current voltage equivalent to motor driving signal RC' outputted from error voltage amplifier 5 while the duty ratio of output pulses of oscillation circuit 6' is varied by signal RC'. |
