| 摘要 |
PURPOSE:To adjust a fade-in and a fade-out speed by using a counted value as a digital signal for resistance value control, and varying the oscillation frequency of an oscillator which supplies up or down count pulses to a counter. CONSTITUTION:An input signal supplied from an input terminal 1 during sound recording is passed through a resistance attenuator 2 whose recording level is set previously by a control circuit 8 and the counter 9 to impress to a sound recording head through a sound recording amplifier 3. When an operation switch SW1 is turned on for fade-out, an R-SFF is set and the output of its terminal Q goes down to a low level to turn off a transistor Q1, putting an oscillating circuit 13 in operation. A pulse signal of frequency set by a variable resistor VR is inputted to the up terminal of the counter 9 and the resistance attenuator 2 performs stepwise attenuation from the preset amount of attenuation. |
