| 摘要 |
PURPOSE:To obtain a desired variable characteristic in a wide range by connecting a constant voltage source to both ends of two PIN diodes connected in series and connecting a variable voltage source to both ends of one PIN diode. CONSTITUTION:A output voltage E0 of an operational amplifier OP2 constituting the constant voltage source is applied to both ends of PIN diodes D1 and D2 connected in series. The output voltage of an operational amplifier OP1 is changed by adjustment of a variable voltage Es, and an output voltage E1 of the operational amplifier OP1 constituting the variable voltage source is applied to both ends of the diode D1. Consequently, the voltage Es is adjusted to change resistance volues of diodes D1 and D2 so that their logarithmic values are inversely proportional to each other, thus obtaining a desired characteristic asa variable equalizer. |
