| 摘要 |
PURPOSE:To obtain superior high frequency characteristics by making the movement length of the unit step of one of two capacitive slugs, loaded at a high-frequency transmission line part, double that of the other. CONSTITUTION:A main capacitive slug 41 is driven by a main step motor 45, and a subordinate capacitive slug 42 is driven by a subordinate step motor. The motor 45 is installed on the same substrate with a high-frequency transmission line 47, but the motor 46 is supported to operate together with the slug 41. The slugs 41 and 42 cooperate with each other and if the distance between the slug 41 and its reference position is l1 and that of the slug 42 and its reference position l2, the l1 and l2 correspond to the high frequency impedance of a tuner in 1:1 proportion. Then, the unit step movement step of the l1 is set double that of the l2, and consequently the quantization of a high frequency generated by digitization is optimized while simple electric and mechanical constitution and easy maintenance are realized. |
