GB2276786B - A voltage controlled filter and a radio communications device comprising the same - Google Patents

A voltage controlled filter and a radio communications device comprising the same

Info

Publication number
GB2276786B
GB2276786B GB9305883A GB9305883A GB2276786B GB 2276786 B GB2276786 B GB 2276786B GB 9305883 A GB9305883 A GB 9305883A GB 9305883 A GB9305883 A GB 9305883A GB 2276786 B GB2276786 B GB 2276786B
Authority
GB
United Kingdom
Prior art keywords
filter
notch
communications device
radio communications
filter characteristic
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.)
Expired - Fee Related
Application number
GB9305883A
Other versions
GB9305883D0 (en
GB2276786A (en
Inventor
Stefan Lichterfeld
Matthias Ernst Konig
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.)
Motorola Solutions Germany GmbH
Original Assignee
Motorola GmbH
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 Motorola GmbH filed Critical Motorola GmbH
Priority to GB9305883A priority Critical patent/GB2276786B/en
Publication of GB9305883D0 publication Critical patent/GB9305883D0/en
Publication of GB2276786A publication Critical patent/GB2276786A/en
Application granted granted Critical
Publication of GB2276786B publication Critical patent/GB2276786B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/0153—Electrical filters; Controlling thereof
    • H03H7/0161—Bandpass filters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1716—Comprising foot-point elements
    • H03H7/1725—Element to ground being common to different shunt paths, i.e. Y-structure
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
    • H03H7/1758—Series LC in shunt or branch path
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
    • H03H7/1766—Parallel LC in series path

Landscapes

  • Control Of Motors That Do Not Use Commutators (AREA)
  • Filters And Equalizers (AREA)

Abstract

In order to obtain a substantially constant passband for a filter of, for example, a radio communications device, a first notch is provided in an upper side of the filter characteristic to define a slope for the upper side of the filter characteristic, thereby substantially fixing the bandwidth of the passband. The notch is generated by high impedance coupling between a capacitor 24, varactors 26, 28 and a resonant circuit 30, 32. A notch on the lower side of the filter characteristic is generated by mutual coupling between inductors 38, 40. A voltage 36 controlled e.g. by a microprocessor, shifts the centre frequency and the pass-band. An alternative arrangement includes two pairs of varactors and separate parallel tuned circuits coupling the filter to input, output terminals. Further notches are introduced by the parallel tuned circuits. The inductors e.g. 32, 38, 40 may be formed by microstrip lines. <IMAGE>
GB9305883A 1993-03-22 1993-03-22 A voltage controlled filter and a radio communications device comprising the same Expired - Fee Related GB2276786B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9305883A GB2276786B (en) 1993-03-22 1993-03-22 A voltage controlled filter and a radio communications device comprising the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9305883A GB2276786B (en) 1993-03-22 1993-03-22 A voltage controlled filter and a radio communications device comprising the same

Publications (3)

Publication Number Publication Date
GB9305883D0 GB9305883D0 (en) 1993-05-12
GB2276786A GB2276786A (en) 1994-10-05
GB2276786B true GB2276786B (en) 1996-07-10

Family

ID=10732510

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9305883A Expired - Fee Related GB2276786B (en) 1993-03-22 1993-03-22 A voltage controlled filter and a radio communications device comprising the same

Country Status (1)

Country Link
GB (1) GB2276786B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2313008B (en) * 1996-05-10 2000-03-15 Roke Manor Research Improvements in or relating to filters
SE514174C2 (en) * 1999-03-09 2001-01-15 Ericsson Telefon Ab L M Variable resonant frequency resonator
AU2003223743A1 (en) * 2002-04-26 2003-11-10 Thomson Licensing S.A. Tuner input filter with electronically adjustable response for adapting to antenna characteristic
CN104104359A (en) * 2014-07-15 2014-10-15 深圳市森虎科技有限公司 Radio frequency filter circuit
CN111416614B (en) * 2020-04-10 2023-10-27 成都仕芯半导体有限公司 High-linearity radio frequency circuit and method for improving linearity of radio frequency circuit

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB988295A (en) * 1963-05-09 1965-04-07 Emi Ltd Voltage variable bandpass filter
GB2247125A (en) * 1990-08-16 1992-02-19 Technophone Ltd Tunable bandpass filter.

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB988295A (en) * 1963-05-09 1965-04-07 Emi Ltd Voltage variable bandpass filter
GB2247125A (en) * 1990-08-16 1992-02-19 Technophone Ltd Tunable bandpass filter.

Also Published As

Publication number Publication date
GB9305883D0 (en) 1993-05-12
GB2276786A (en) 1994-10-05

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20050322