| 摘要 |
PURPOSE:To improve the effective sensitivity and the input characteristic, by inserting a matching circuit including an inductance and a varactor diode between an antenna and an RF amplifier of a receiver. CONSTITUTION:Between an antenna and an RF amplifier of a receiver, a matching circuit (b) having connected in series the parallel connection of an inductance L1, inductance L2 and varactor diode Cv is inserted. Thus, the impedance viewing left from B-B' is an impedance with a high pure resistance and the ratio of antenna induced voltage ea at the resonant point to output voltage eo at a B-B' terminal has selectivity taking the resonant point as a peak. |
