| 摘要 |
PURPOSE:To improve the efficiency of an antenna unit by covering the coil of a tuning part with a material of high permeablity while leading an antenna part out of an armored cable. CONSTITUTION:On the primary side, a series resonating circuit is constituted and a signal induced at primary coil 3 is extracted by secondary coil 4 and led to an amplifying circuit. Coils 3 and 4 are completely covered with high-permeablity substance 5 such as ferrite and permalloy to prevent an eddy current from being generated due to the induction of magnetic flux leaking from coils 3 and 4 to armored case 2, a metal conductor, thereby constituting a tuning circuit with a little loss, i.e., with high Q. |
