| 摘要 |
PROBLEM TO BE SOLVED: To obtain stable frequency characteristics, in spite of an influence from a variation in elemental characteristics, temperature characteristics, and power voltage characteristics. SOLUTION: LPFs 2, 3 are provided in parallel with an input terminal 1. The LPF 2 has a time constant circuit for realizing a low pass characteristic as the base. The LPF 3 has the same time constant circuit as that of the LPF 2 and the frequency near to the cut off frequency of the LPF 2 becomes a boost frequency in the LPF 3. The LPF 3 generates a signal having a polarity reverse to that of the LPF 2. Then, the output of the LPF 3 is subtracted from the output of the LPF 2 in a subtracter 4, and a signal filtered with a pass band that is shifted to a wide band range is obtained at an output terminal 5. COPYRIGHT: (C)2004,JPO
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