Document Type and Number:
Japanese Patent JPS6232845
Kind Code:
B2
Abstract:
A capacitor trimming system for a quartz-crystal oscillator in a watch and/or a clock for providing a punctual watch and/or a clock has been found. The system comprises an oscillation circuit including at least a quartz-crystal piece, a trimmer capacitor for adjusting the oscillating frequency of the quartz-crystal piece, a semiconductor electronic circuit for operating said quartz-crystal piece, and apparatus for adjusting automatically the trimmer capacitor so that the oscillating frequency becomes the same as the desired reference frequency. The trimmer capacitor comprises of at least a fixed outer trimming electrode, an inner common electrode fixed parallel to said trimming electrode and a dielectric body sandwiched between the two electrodes. The trimming electrode is disposed in the air for enabling the trimming of the area of the trimming electrode, and the trimming electrode has a coarse adjustment portion parallel and aligned with said common electrode and a fine adjustment portion attached to the same plane of that of the coarse adjustment portion but outside of the common electrode. The oscillation frequency of the quartz-crystal piece is automatically picked up and the frequency is compared with the desired reference frequency, and according to the result of the comparison, the trimming electrode is trimmed so that the oscillating frequency becomes the desired reference frequency. The trimming is carried out first for the coarse trimming portion, and secondly for the fine adjustment portion.
Inventors:
MASUJIMA MASARU
IWATANI SHOICHI
IWATANI SHOICHI
Application Number:
JP14846978A
Publication Date:
July 17, 1987
Filing Date:
November 30, 1978
Export Citation:
Assignee:
TDK ELECTRONICS CO LTD
International Classes:
G04D7/12; G04G3/00; H01G4/255; H03B5/32; H03H3/04; H03H9/05; H03L7/00