| 摘要 |
PURPOSE:To automatically set the most suitable sound recording bias current, sound recording level, and sound recording equalizer characteristic to magnetic tapes of any characteristics, by using a microcomputer of a stored program system. CONSTITUTION:To a sound recording bias current, initial data are outputted from a port output PD of a PIA3 and converted into a DC level by a D/A converter 30 and the bias current value of a bias oscillator 32 to a sound recording head 4 is controlled. A sound recording level is initialized to an appropriate value in such a way that data from another port output of the PIA3 are converted into a DC level by another converter 24 and a VCA22 is controlled through a buffer amplifier 23. A sound recording equalizer is initialized to an appropriate equalizer characteristic in such a way that data are outputted from a port PC of the PIA3 and converted into a DC level by a D/A converter 28 and a variable capacity circuit C is controlled through a buffer amplifier 27, and then, the appropriate equalizer characteristic is initialized at a sound recording equalizer controlling circuit 25 on the basis of the value of a coil L and the variable capacity circuit C. |
