ANTENNA TUNING AND MATCHING CIRCUIT FOR SOLIDIFIED SHORT-WAVE TRANSMITTER

摘要

PROBLEM TO BE SOLVED: To attenuate the low-frequency part of a lightning surge by simple connection changes of the circuit and to maintain a function for matching antenna impedance by grounding the other end of the free turn of a variable coil ahead of a roll contact and forming a single turning circuit, with has a turning frequency by using the inductance and capacitor at the free-turn part. ;SOLUTION: The terminal of the load-side free turn of a variable coil L2 is grounded, and the single turning circuit is formed of the inductance and capacitor C3 at the free-turn part of the variable coil L2 to attenuate the frequency component of the low band. The tuning frequency of the single turning circuits is set lower than a transmission frequency, and then a double-π circuit is equivalently obtained in the case of the transmission frequency. Here, since the capacitance of the capacitor C3 at this time needs to cancel the inductance of the free-turn part of the variable coil L2 in the case of the transmission frequency, it is adjusted to be larger than that before the free turn of the variable coil L2 is grounded.;COPYRIGHT: (C)1998,JPO