| 摘要 |
PURPOSE:To improve the linearity and to extend dynamic range, by applying a voltage a half an instantaneous value of an input signal voltage in addition to a control voltage between the source and drain of an FET. CONSTITUTION:When an AC voltage is applied to an input terminal 5 by taking a voltage of a bias power supply 4 as a center, an output voltage is generated at a terminal 6 so that an inverting input terminal voltage of a high gain amplifier 1 can be the same as the voltage at the input terminal 5. Thus, a voltage the same as an input voltage is applied between the dain and source of an FET3. Since this voltage is also applied to a series circuit consisting of resistor 9 and 10 at the same time, a voltage at connecting point of the resistors 9, 10 is an intermediate potential just between the source and the drain of the FET3. A control input is inutted via a resistor 12 and a capacitor 11 is connected between the connecting point of the resistors 9 and 10 and the gate, then almost no input signal voltage is applied to the gate, but only the control voltage is applied. That is, a half the input signal component voltage is applied between the source and the gate in addition to the control voltage. |
