Invention Application
- Patent Title: Filter control apparatus and filter system
- Patent Title (中): 过滤器控制装置和过滤系统
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Application No.: US11151343Application Date: 2005-06-14
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Publication No.: US20050280476A1Publication Date: 2005-12-22
- Inventor: Kazuhide Abe , Michihiko Nishigaki , Toshihiko Nagano , Ryoichi Ohara , Hiroshi Yoshida , Hiroshi Tsurumi , Takashi Kawakubo
- Applicant: Kazuhide Abe , Michihiko Nishigaki , Toshihiko Nagano , Ryoichi Ohara , Hiroshi Yoshida , Hiroshi Tsurumi , Takashi Kawakubo
- Applicant Address: JP Tokyo
- Assignee: KABUSHIKI KAISHA TOSHIBA
- Current Assignee: KABUSHIKI KAISHA TOSHIBA
- Current Assignee Address: JP Tokyo
- Priority: JP2004-177443 20040615
- Main IPC: H03B21/01
- IPC: H03B21/01 ; H03H7/01 ; H03L7/00 ; H03L7/07 ; H03L7/081 ; H03L7/099

Abstract:
A filter control apparatus which controls a frequency variable filter capable of changing a transmission band width by controlling a capacitance of at least a portion of a plurality of voltage variable capacitors connected in series and parallel to a resonator has an input unit, and a filter control circuit. The input unit inputs a reference signal with a predetermined reference frequency to the frequency variable filter. The filter control circuit controls a center frequency and the transmission band width of the frequency variable filter by detecting a phase change generated when the reference signal passes through the frequency variable filter and by variably controlling the capacitance of at least a portion of the voltage variable capacitor by using a direct voltage in proportion to the phase change.
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