| 摘要 |
PROBLEM TO BE SOLVED: To precisely adjust the center frequency and the band width of a duplex mode filter element and to eliminate the need of connection man-hours between the elements by conducting and connecting first and second lead electrodes and two terminal electrode and cascade-connecting them. SOLUTION: A duplex mode filter where two groups of input/output electrodes 3a, 4a, 3b and 4b are formed on a piezoelectric substrate 2 and common electrodes 5a and 5b on the opposite confronting parts is constituted to be independent of h cascade connection type filter element F2 and from lead electrodes L1-L6. The elements F2 are formed at the surface/back face of a wafer U in a matrix form and the frequencies of the duplex mode filter elements are individually measured. In the adjustment of the center frequency and the band width of the element F2, the wafer U is put in a vacuum device, plural probes are brought into contact with the lead electrodes L1-L3, the frequency is measured and mass is added to the electrodes 3a-5a or it is removed if need. Thus, the whole duplex mode filter elements formed in the matrix forms of the wafer U are adjusted.
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