| 摘要 |
PURPOSE:To enable continuous change of the value of Q of a tuning circuit that uses a tuning coil, a capacitance and an FET by making the gate voltage of the FET continuously variable. CONSTITUTION:A tuning coil L, a capacitor C and a resistor (R) 1 are connected in parallel between an input terminal 1 and ground. Further, a drain of a TR consisting of an R2 and an FET is connected and the other end of R2 is connected to a terminal 1, and the source of the FET is grounded. The gate of the FET is connected to a control input terminal 2. By changing the control voltage of the terminal 2 and changing the voltage between the drain and source of the FET, the resistance between the drain and source of the FET is made variable, and the value of Q of a single tuning circuit formed between the terminal 1 and ground can be changed continuously. |
