| 摘要 |
<p>PROBLEM TO BE SOLVED: To decrease the number of parts and also to reduce the area of a circuit for the reduction of both size and cost of a VCO by trimming a frequency adjustment inductor via a laser beam machine to oscillate the VCO frequency at a prescribed level. SOLUTION: The inductors MS1 and MS2 are formed in the copper foil circuit patterns, and the necessary inductance is given to each inductor according to the width, length and bending shape of the pattern. One of both ends of the MS2 and the anode of a diode D1 are connected to a ground plane formed on the backside via a through-hole TH, and the inductance of the MS2 is adjusted to secure the desired output frequency. The circuit component parts excluding the inductors are mounted on a printed circuit board to construct a VCO. Then the intermediate part of the MS2 is irradiated by a laser beam for trimming a groove G. Thus, the inductance of the MS2 is adjusted so that the oscillation frequency is adjusted at a desired level.</p> |
