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Patent Searching and Data


Title:
VARIABLE-FREQUENCY FILTER, RF FRONT END CIRCUIT, AND COMMUNICATION TERMINAL
Document Type and Number:
WIPO Patent Application WO/2017/170071
Kind Code:
A1
Abstract:
A first attenuating circuit (13) is connected between earth and a node connected between a ladder-type resonance circuit (11) and a transmitting side terminal (Ptx). A second attenuating circuit (14) is connected to earth and to a first parallel arm resonator (115) of the ladder-type resonance circuit (11), and is connected in series with the first parallel arm resonator (115). The first attenuating circuit (13) includes: a second parallel arm resonator (132); and a first switch (131) which switches between a first state in which the second parallel arm resonator (132) and the node are electrically connected to one another, and a second state in which the switch is open. The second attenuating circuit (14) includes: a capacitor (142); and a second switch (141) which switches between a first state in which the capacitor (142) and the first parallel arm resonator (115) are electrically connected to one another, and a second state in which the first parallel arm resonator (115) is electrically connected to earth. When the first switch is in the first state, the second switch is in the first state.

Inventors:
TSUKAMOTO HIDEKI (JP)
TANI MASAKAZU (JP)
MATSUTANI KEI (JP)
Application Number:
PCT/JP2017/011573
Publication Date:
October 05, 2017
Filing Date:
March 23, 2017
Export Citation:
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Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H7/075; H03H7/12
Foreign References:
US20090251235A12009-10-08
JP2013239839A2013-11-28
JP2009165066A2009-07-23
JP2008301223A2008-12-11
Attorney, Agent or Firm:
KAEDE PATENT ATTORNEYS' OFFICE (JP)
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