| 摘要 |
PROBLEM TO BE SOLVED: To provide a newly-developed variable filter capable of varying pass characteristics by using an appropriate external control means. SOLUTION: The filter is provided with serial thin film piezoelectric resonators 11 which are connected serially to an input and an output, parallel thin film piezoelectric resonators 12 which are connected in parallel to the input and the output, and a variable voltage circuit 13 capable of varying the applying voltage of either the resonators 11 or the resonators 12. The resonant characteristic of at least either the resonators 11 or the resonators 12 is shifted by varying the voltage of the circuit 13, thereby varying the pass characteristics. COPYRIGHT: (C)2003,JPO
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