| 摘要 |
<p>PURPOSE:To attain trimming at a high speed by measuring a capacitance of each capacitor deciding its frequency characteristic and inputting a resistance calculated from the actually measured value as a program data. CONSTITUTION:An active filter such as a 7th-order LPF consists of seven capacitors (capacitance C1, C2, C3-C7) seven resistors (resistances R1, R2, R3-R7) and amplifiers (A1, A2, A3). Then an IC (amplifier) and a capacitor are mounted on the printed circuit board with a print circuit formed thereupon and the resistors are printed on the printed circuit board. Through the constitution above, the mounted boards is fitted to a trimmer, the capacitors C1-C7 are measured actually at a high speed by means of an impedance meter of the trimmer system, and the obtained data is given to a transfer function equation shown in equations programmed by the computer of the trimmer system. The resistances R1-R7 are calculated at a high speed by the transfer function equation and the resistors on the printed circuit board are trimmed to the resistances.</p> |
