| 摘要 |
A tuning circuit for preventing deterioration of a Q value is provided to improve an RF(Radio Frequency) characteristic by preventing an expansion of a bandwidth. In a tuning circuit for preventing deterioration of a Q value, a first circuit(K1) connects a first variable-capacity device and a second variable-capacity device(31a,31b) in series. An inductance device(23a,23b) is connected to the first circuit(K1) in parallel. The inductance device(23a,23b) forms a resonance circuit with the first circuit(K1). A second circuit(K2) has a switch device(26a,26b) and a third resistor(27a,27b) connected to each other in series. The second circuit(K2) is connected to the first circuit(K1) in parallel. First and second resistors(24a,24b,25a,25b) are connected to both ends of the first variable-capacity device. The first and second resistors(24a,24b,25a,25b) apply a predetermined tuning voltage(Vt). |
