GB533171A - Wave filter - Google Patents
Wave filterInfo
- Publication number
- GB533171A GB533171A GB27845/39A GB2784539A GB533171A GB 533171 A GB533171 A GB 533171A GB 27845/39 A GB27845/39 A GB 27845/39A GB 2784539 A GB2784539 A GB 2784539A GB 533171 A GB533171 A GB 533171A
- Authority
- GB
- United Kingdom
- Prior art keywords
- mid
- frequencies
- band
- capacities
- band frequency
- 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
Links
- 239000013078 crystal Substances 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/0023—Balance-unbalance or balance-balance networks
- H03H9/0095—Balance-unbalance or balance-balance networks using bulk acoustic wave devices
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/542—Filters comprising resonators of piezoelectric or electrostrictive material including passive elements
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Filters And Equalizers (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
533,171. Impedance networks. STANDARD TELEPHONES & CABLES, Ltd. Oct. 13, 1939, No. 27845. Convention date, Nov. 5, 1938. [Class 40 (iii)] In a band-pass lattice filter employing piezo-electric elements, instead of the series and diagonal branches Z<SP>1</SP>, Z2 having anti-resonance and resonance frequencies coinciding with the mid-band frequency f4, as indicated in Fig. 3, these critical frequencies f3,f5 are spaced slightly on either side of the mid-band frequency, as in Fig. 4. This produces a small hump in the attenuation curve and improves the distortion and cut-off properties of the filter, as well as increasing the available band-width. The attenuation at the mid-band frequency f4 is preferably made equal to that at the cut-off frequencies f2, f6. The shifting of the critical frequencies is obtained by having one pair of crystals slightly longer than the other pair, and by increasing the values of the shunt capacities. These capacities may be wholly or partly replaced by shunt capacities at the ends of the network.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US238991A US2216937A (en) | 1938-11-05 | 1938-11-05 | Wave filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB533171A true GB533171A (en) | 1941-02-07 |
Family
ID=22900166
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB27845/39A Expired GB533171A (en) | 1938-11-05 | 1939-10-13 | Wave filter |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US2216937A (en) |
| FR (1) | FR861340A (en) |
| GB (1) | GB533171A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL75153C (en) * | 1947-11-21 | |||
| US2929031A (en) * | 1957-02-06 | 1960-03-15 | Hermes Electronics Co | Intermediate band width crystal filter |
| US2990525A (en) * | 1957-12-12 | 1961-06-27 | Bell Telephone Labor Inc | Wave filter |
| JP3389911B2 (en) * | 2000-02-07 | 2003-03-24 | 株式会社村田製作所 | Surface acoustic wave filter, duplexer and communication device |
| JP2002152008A (en) * | 2000-11-06 | 2002-05-24 | Alps Electric Co Ltd | Lattice type filter |
| EP1588487A2 (en) * | 2003-01-20 | 2005-10-26 | Koninklijke Philips Electronics N.V. | Resonator filter structure having equal resonance frequencies |
| FR2973970B1 (en) | 2011-04-07 | 2013-04-12 | Commissariat Energie Atomique | DEVICE USING A FILTER BASED ON RESONATORS |
-
1938
- 1938-11-05 US US238991A patent/US2216937A/en not_active Expired - Lifetime
-
1939
- 1939-10-13 GB GB27845/39A patent/GB533171A/en not_active Expired
- 1939-11-04 FR FR861340D patent/FR861340A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR861340A (en) | 1941-02-06 |
| US2216937A (en) | 1940-10-08 |
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