| 摘要 |
PURPOSE:To eliminate the interference between the circuits at the high and low bands by constituting the feedback circuit and the output circuit of the noninverse amplifier with the circuit in which the parallel circuit of the resistance and the capacitor and the pi-type circuit of the resistance and the capacitor. CONSTITUTION:The voltage applied to terminal IN is applied to the noninverse input end of noninverse amplifier 40, and the output end is connected with the parallel circuit of resistance 41 and capacitor 42 plus resistance 43 in series. Resistance 47 and variable resistor 48 are connected in series to the joint of resistances 41 and 43. Resistance 50, capacitor 51 and variable resistor 52 are connected in series to the other end of resistance 43, and the joint of resistances 43 and 50 is connected to output terminal OUT. On the other hand, the output point of the circuit comprising resistances 44, 46 and 54, capacitors 45 and 53 plus variable resistors 48 and 52 is connected to the noninverse input terminal of amplifier 40. As a result, the interference especially between the hihg-sound side circuit and the low-sound side circuit can be eliminated. And the variable resistor featuring the linearity of the rotary angle/resistance variation ratio characteristics is used to secure the equal variation rate for the boost and cut quantity between the high sound and the low sound. |
