EP0818883A3 - Duplex filter - Google Patents

Duplex filter Download PDF

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Publication number
EP0818883A3
EP0818883A3 EP97304719A EP97304719A EP0818883A3 EP 0818883 A3 EP0818883 A3 EP 0818883A3 EP 97304719 A EP97304719 A EP 97304719A EP 97304719 A EP97304719 A EP 97304719A EP 0818883 A3 EP0818883 A3 EP 0818883A3
Authority
EP
European Patent Office
Prior art keywords
filter
stage
filter stage
stages
saw
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97304719A
Other languages
German (de)
French (fr)
Other versions
EP0818883A2 (en
Inventor
Harri Närhi
Erkki Niiranen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pulse Finland Oy
Original Assignee
LK Products Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LK Products Oy filed Critical LK Products Oy
Publication of EP0818883A2 publication Critical patent/EP0818883A2/en
Publication of EP0818883A3 publication Critical patent/EP0818883A3/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/213—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies

Landscapes

  • Control Of Motors That Do Not Use Commutators (AREA)
  • Non-Reversible Transmitting Devices (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

The invention relates to a radio-frequency filter with a good temperature stability and power handling capacity. The invention can be applied in the pre-stages of portable mobile telephone apparatuses, for example. The receiver branch (2) of the filter construction according to the invention employs two filter stages (3, 4), the first of which (3) attenuates the signal connected to the second filter stage, said second filter stage being a SAW filter (4). Said first filter stage (3) can be realized with a helix or dielectric resonator, for example. In a second embodiment of the invention, said first filter stage (3) is used to compensate for changes caused by the temperature dependence of the frequency response of the SAW filter (4).
EP97304719A 1996-07-11 1997-06-30 Duplex filter Withdrawn EP0818883A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI962815A FI962815A0 (en) 1996-07-11 1996-07-11 The duplex filter
FI962815 1996-07-11

Publications (2)

Publication Number Publication Date
EP0818883A2 EP0818883A2 (en) 1998-01-14
EP0818883A3 true EP0818883A3 (en) 1998-09-09

Family

ID=8546372

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97304719A Withdrawn EP0818883A3 (en) 1996-07-11 1997-06-30 Duplex filter

Country Status (2)

Country Link
EP (1) EP0818883A3 (en)
FI (1) FI962815A0 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11154804A (en) * 1997-11-20 1999-06-08 Hitachi Ltd High frequency circuit device
JP3704442B2 (en) * 1999-08-26 2005-10-12 株式会社日立製作所 Wireless terminal
JP2001345662A (en) * 2000-05-31 2001-12-14 Murata Mfg Co Ltd Duplexer and mobile communication equipment using the same
JP3889351B2 (en) 2002-12-11 2007-03-07 Ｔｄｋ株式会社 Duplexer

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59108407A (en) * 1982-12-14 1984-06-22 Nec Corp Temperature compensating type elastic surface wave oscillator
US4509165A (en) * 1981-12-22 1985-04-02 Nippon Electric Co., Ltd. Miniaturized antenna duplexer using SAW filter
EP0614242A1 (en) * 1993-03-03 1994-09-07 Lk-Products Oy Electrical filter
EP0678973A1 (en) * 1994-04-18 1995-10-25 NEC Corporation Receiving circuit for generating intermediate frequency signal having frequency characteristics independent of variations in temperature

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4509165A (en) * 1981-12-22 1985-04-02 Nippon Electric Co., Ltd. Miniaturized antenna duplexer using SAW filter
JPS59108407A (en) * 1982-12-14 1984-06-22 Nec Corp Temperature compensating type elastic surface wave oscillator
EP0614242A1 (en) * 1993-03-03 1994-09-07 Lk-Products Oy Electrical filter
EP0678973A1 (en) * 1994-04-18 1995-10-25 NEC Corporation Receiving circuit for generating intermediate frequency signal having frequency characteristics independent of variations in temperature

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 008, no. 229 (E - 273) 20 October 1984 (1984-10-20) *

Also Published As

Publication number Publication date
FI962815A0 (en) 1996-07-11
EP0818883A2 (en) 1998-01-14

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