| 摘要 |
PURPOSE:To change the variation of a sound volume to continuous one, by providing a variable impedance circuit which is operable from the outside of the apparatus equipped with the circuit and divides an erasing current supplied from a bias oscillator to an erasing magnetic head. CONSTITUTION:A variable resistor 7 has such a resistance value changing characteristic that, when a recorded tape is loaded and a conducted condition is set by closing a switch 6, the resistance value changes so that the electric current flowing to an erasing head 1 can change within the extention between points A and B and, since the extent between the points A and B is very narrow, the changing quantity of the resistance value against the rotating angle is extremely small. When operations are made to gradually increase the sound volume, the erasing current changes from the point B to the point A, if the erasing operation is made and the variable resistor 7 is changed in the direction, in which the resistance value is damped. In case when the sound value is gradually decreased, the erasing current changes from the point A to the point B, if the erasing operation is made and the variable resistor 7 is changed in the direction, in which the resistance value is increased. Therefore, the recorded condition of magnetic tapes, on which sounds are interrupted in the course of recording or recording is performed from the midway, can be corrected in such a way that the recording is performed by gradually changing the sound value. |
