US2994047A - Mechanical filter coupling - Google Patents
Mechanical filter coupling Download PDFInfo
- Publication number
- US2994047A US2994047A US777906A US77790658A US2994047A US 2994047 A US2994047 A US 2994047A US 777906 A US777906 A US 777906A US 77790658 A US77790658 A US 77790658A US 2994047 A US2994047 A US 2994047A
- Authority
- US
- United States
- Prior art keywords
- coupling
- resonators
- filter
- bores
- mechanical filter
- 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 - Lifetime
Links
Images
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
- H03H9/46—Filters
- H03H9/48—Coupling means therefor
- H03H9/50—Mechanical coupling means
Definitions
- the present invention relates to mechanical frequency filters and, especially, to means for varying the coupling between individual elements of the filters.
- a mechanical frequency filter comprising a plurality of mechanically coupled resonant bodies to be energized in torsional oscillation, said resonant bodies being coupled with each other by means of longitudinally oscillating coupling lines or wires.
- cylindrical resonant bodies are suitably used which are arranged adjacent one another with their axes mutually parallel. These bodies are interconnected to form a ladder-like structure by means of wires serving as coupling means and running perpendicularly to the axes of the bodies.
- the coupling coeflicient depends upon the diameters of the bores through the resonant bodies to be coupled with one another, so that the coupling can be readily adjusted to the desired value by suitably dimensioning these bores.
- FIGURE 1 is a perspective view of a part or a system of filters employing difierent degrees of coupling between individual filter resonators, according to the invention
- FIGURE 2 is an enlarged end view or a resonator according to the present invention.
- FIGURE 3 is a plan view of a to the present invention.
- FIGURE 4 is a side view of FIGURE 3.
- FIGURE 1 three cylindrical resonators 1, 2 and 3, energized in torsional oscillation, are mutually coupled by means of coupling wires 4, 5, 6 and 7.
- the resonators ;1 and 2 are provided with cylindrical coaxial bores 8 and 9, respectively, so that the resonators are hollow cylindrical bodies, while the resonator body 3 constitutes a solid cylinder.
- the coupling between two adjacent resonators is dependent upon the constants of the material, i.e., the density p and the velocity of mechanical propagation v, upon the cross sectional area of the resonators, the area of filter system according the system according to 2,994,047 Patented July 25, 1961 ice the bores and the area of the coupling wires.
- F denotes the total cross sectional area of the resonators including bore, while F denotes the cross sectional area of the bore, as shown in cross section in FIGURE 2.
- the coupling coetficient between two adjacent resonators of the same kind can be calculated according to the following equation:
- the coupling coefiicient can be calculated with the aid of the following equation:
- FIGURES 3 and 4 show a system of mechanical filters comprising seven resonators, 11, 12, 13, 14, 15, 1 6 and 17.
- Longitudinally oscillating magneto-strictive transducers 18 and 19 are provided to energize the filter, said transducers being magnetized in a manner known per so by means of a permanent magnet (not shown) and being coupled to external electric circuits (not shown) by means of a coil (also not shown).
- the bores of the outermost resonators 11 and 17 have larger diameters than the bores of the inner resonators, whereby the sizes of the diameter are gradually increased starting from the center resonator 114 towards the outer resonators 11 and 17. As a result of this, the coupling increases towards the outside between the individual filter resonators, as required by theoretical considerations.
- a mechanical tuned filter including a plurality of axially parallel cylindrical resonators to be energized in torsional oscillation and all resonant at the same frequency, and said resonators being coupled with one another by means of longitudinally oscillating coupling wires joined tangentially to said cylinders, the improvement characterized by providing at least one of the resonators with a coaxial bore therein, the diameter of the bore serving to determine the coefficient of coupling be tween the associated resonator and adjacent resonators.
- At least three resonators comprising said filter, and at least two of said resonators having bores therein and arranged in such a manner that the diameters of the bores symmetrically increase from the center of the filter towards the outer ends thereof.
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Description
July 25, 1961 M GRNER 2,994,047
MECHANICAL FILTER COUPLING Filed Dec. 3, 1958 MANFRED B6RNER PATENT AGENT United States Patent O 2,994,047 MECHANICAL FILTER COUPLING Manfred Biirner, Ulm (Danube), Germany, assignor to Telefunken G.m.b.li[., Berlin, Germany Filed Dec. 3, 1958, Ser. No. 777,906 Claims priority, application Germany Dec. 11, 1957 2 Claims, (Cl. 33371) The present invention relates to mechanical frequency filters and, especially, to means for varying the coupling between individual elements of the filters.
The copending application, Serial No. 693,681, filed Oct. 31, 1957, relates to a mechanical frequency filter comprising a plurality of mechanically coupled resonant bodies to be energized in torsional oscillation, said resonant bodies being coupled with each other by means of longitudinally oscillating coupling lines or wires. For this purpose, cylindrical resonant bodies are suitably used which are arranged adjacent one another with their axes mutually parallel. These bodies are interconnected to form a ladder-like structure by means of wires serving as coupling means and running perpendicularly to the axes of the bodies. In the aforementioned application, means are disclosed for making the coupling coeflicients between the individual resonant cylinders of different magnitude, i.e., by applying the coupling wires to suitable points of difierent oscillating amplitude on the individual resonant bodies.
For reasons of manufacture, it is often desirable to use stretched, substantially straight coupling wires with the result, that the adjusting means described in the abovementioned copending application cannot be used for adjusting the coupling coetficients.
It is an object of the present invention to obtain diiferent coupling coetficients for the individual resonant cylinders by providing at least one, or preferably several, resonant cylinders with a coaxial central bore of suitable diameter. In the following, it be explained how the coupling coeflicient depends upon the diameters of the bores through the resonant bodies to be coupled with one another, so that the coupling can be readily adjusted to the desired value by suitably dimensioning these bores.
Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and mod cations within the spirit and scope of the invention will become apparent to those skilled in the ant from this detailed description.
In the drawings:
FIGURE 1 is a perspective view of a part or a system of filters employing difierent degrees of coupling between individual filter resonators, according to the invention;
FIGURE 2 is an enlarged end view or a resonator according to the present invention;
FIGURE 3 is a plan view of a to the present invention;
FIGURE 4 is a side view of FIGURE 3.
According to FIGURE 1, three cylindrical resonators 1, 2 and 3, energized in torsional oscillation, are mutually coupled by means of coupling wires 4, 5, 6 and 7. In this embodiment, the resonators ;1 and 2 are provided with cylindrical coaxial bores 8 and 9, respectively, so that the resonators are hollow cylindrical bodies, while the resonator body 3 constitutes a solid cylinder.
The coupling between two adjacent resonators is dependent upon the constants of the material, i.e., the density p and the velocity of mechanical propagation v, upon the cross sectional area of the resonators, the area of filter system according the system according to 2,994,047 Patented July 25, 1961 ice the bores and the area of the coupling wires. F denotes the total cross sectional area of the resonators including bore, while F denotes the cross sectional area of the bore, as shown in cross section in FIGURE 2. The coupling coetficient between two adjacent resonators of the same kind can be calculated according to the following equation:
wherein the parameters relating to the material of the resonators have no subscripts, and those of the coupling wires are provided with the subscript k, and wherein f denotes the total cross sectional area of the coupling w1res.
If the coupled systems have different cross sections F different bores F and/or different properties of the material p, v, the coupling coefiicient can be calculated with the aid of the following equation:
K in 2 pkvkfk wherein the subscripts 1 and 2 relate to the respective parameters of one or the other resonator.
It can be seen that the coupling coefficient between two adjacent resonators is increased when the diameter of the bore is increased in the respective resonators.
FIGURES 3 and 4 show a system of mechanical filters comprising seven resonators, 11, 12, 13, 14, 15, 1 6 and 17. Longitudinally oscillating magneto- strictive transducers 18 and 19 are provided to energize the filter, said transducers being magnetized in a manner known per so by means of a permanent magnet (not shown) and being coupled to external electric circuits (not shown) by means of a coil (also not shown). The bores of the outermost resonators 11 and 17 have larger diameters than the bores of the inner resonators, whereby the sizes of the diameter are gradually increased starting from the center resonator 114 towards the outer resonators 11 and 17. As a result of this, the coupling increases towards the outside between the individual filter resonators, as required by theoretical considerations.
I claim:
1. In a mechanical tuned filter including a plurality of axially parallel cylindrical resonators to be energized in torsional oscillation and all resonant at the same frequency, and said resonators being coupled with one another by means of longitudinally oscillating coupling wires joined tangentially to said cylinders, the improvement characterized by providing at least one of the resonators with a coaxial bore therein, the diameter of the bore serving to determine the coefficient of coupling be tween the associated resonator and adjacent resonators.
2. In a mechanical filter according to claim 1, at least three resonators comprising said filter, and at least two of said resonators having bores therein and arranged in such a manner that the diameters of the bores symmetrically increase from the center of the filter towards the outer ends thereof.
References Cited in the file of this patent UNITED STATES PATENTS 1,933,306 Berry et al. Oct. 31, 1933 2,552,139 Bocciarelli May 8, 1951 2,762,985 George Sept. 11, 1956 2,799,832 Niederman et al July 16, 1957 2,802,992 Doelz Aug. 13, 1957 2,810,888 George et al. Oct. 22, 1957 2,926,315 George Feb. 23, 1960
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE892922T | 1957-12-12 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2994047A true US2994047A (en) | 1961-07-25 |
Family
ID=32332149
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US693681A Expired - Lifetime US3086182A (en) | 1957-12-12 | 1957-10-31 | Mechanical frequency filters |
US777906A Expired - Lifetime US2994047A (en) | 1957-12-12 | 1958-12-03 | Mechanical filter coupling |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US693681A Expired - Lifetime US3086182A (en) | 1957-12-12 | 1957-10-31 | Mechanical frequency filters |
Country Status (7)
Country | Link |
---|---|
US (2) | US3086182A (en) |
CH (2) | CH353096A (en) |
FR (1) | FR1184459A (en) |
GB (2) | GB842756A (en) |
IT (1) | IT616267A (en) |
NL (4) | NL221977A (en) |
SE (1) | SE178175C1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3238476A (en) * | 1960-05-14 | 1966-03-01 | Telefunken Patent | Electrostrictive torsional vibrator |
US3296562A (en) * | 1962-09-21 | 1967-01-03 | Telefunken Patent | Electromechanical filter |
US3931600A (en) * | 1973-06-11 | 1976-01-06 | Kokusai Electric Co., Ltd. | Mechanical filter |
US4241321A (en) * | 1978-02-15 | 1980-12-23 | Fujitsu Limited | Electromechanical filter |
US4349903A (en) * | 1979-02-02 | 1982-09-14 | Licentia Patent-Verwaltungs-G.M.B.H. | Switching of channels between two premodulation systems |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE622705A (en) * | 1961-09-22 | |||
GB1041375A (en) * | 1962-06-28 | 1966-09-07 | Telefunken Patent | Mechanical frequency filter |
DE2142332C2 (en) * | 1971-08-24 | 1983-07-14 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Mechanical filter and method of making the filter |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1933306A (en) * | 1931-04-30 | 1933-10-31 | Gen Electric | Electrical frequency analyzer |
US2552139A (en) * | 1948-06-17 | 1951-05-08 | Philco Corp | Electrical system |
US2762985A (en) * | 1952-09-20 | 1956-09-11 | Rca Corp | Mechanically resonant filter devices |
US2799832A (en) * | 1953-09-11 | 1957-07-16 | Motoroln Inc | Electromechanical filter |
US2802992A (en) * | 1953-05-07 | 1957-08-13 | Collins Radio Co | Elimination of spurious response in an electromechanical filter |
US2810888A (en) * | 1954-08-03 | 1957-10-22 | Rca Corp | Electromechanical filter |
US2926315A (en) * | 1956-08-27 | 1960-02-23 | Rca Corp | Electromechanical filter |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2615981A (en) * | 1949-01-14 | 1952-10-28 | Collins Radio Co | Electromechanical filter |
US2736824A (en) * | 1950-12-21 | 1956-02-28 | Rca Corp | Magnetostrictive ferrites |
US2856588A (en) * | 1956-03-01 | 1958-10-14 | Rca Corp | Mechanical filter |
-
0
- NL NL113914D patent/NL113914C/xx active
- IT IT616267D patent/IT616267A/it unknown
- NL NL233996D patent/NL233996A/xx unknown
- NL NL114041D patent/NL114041C/xx active
- NL NL221977D patent/NL221977A/xx unknown
-
1957
- 1957-10-05 CH CH353096D patent/CH353096A/en unknown
- 1957-10-17 FR FR1184459D patent/FR1184459A/en not_active Expired
- 1957-10-31 US US693681A patent/US3086182A/en not_active Expired - Lifetime
- 1957-11-01 GB GB34157/57A patent/GB842756A/en not_active Expired
-
1958
- 1958-09-26 CH CH358874D patent/CH358874A/en unknown
- 1958-10-24 SE SE988658A patent/SE178175C1/xx unknown
- 1958-11-26 GB GB38111/58A patent/GB892922A/en not_active Expired
- 1958-12-03 US US777906A patent/US2994047A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1933306A (en) * | 1931-04-30 | 1933-10-31 | Gen Electric | Electrical frequency analyzer |
US2552139A (en) * | 1948-06-17 | 1951-05-08 | Philco Corp | Electrical system |
US2762985A (en) * | 1952-09-20 | 1956-09-11 | Rca Corp | Mechanically resonant filter devices |
US2802992A (en) * | 1953-05-07 | 1957-08-13 | Collins Radio Co | Elimination of spurious response in an electromechanical filter |
US2799832A (en) * | 1953-09-11 | 1957-07-16 | Motoroln Inc | Electromechanical filter |
US2810888A (en) * | 1954-08-03 | 1957-10-22 | Rca Corp | Electromechanical filter |
US2926315A (en) * | 1956-08-27 | 1960-02-23 | Rca Corp | Electromechanical filter |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3238476A (en) * | 1960-05-14 | 1966-03-01 | Telefunken Patent | Electrostrictive torsional vibrator |
US3296562A (en) * | 1962-09-21 | 1967-01-03 | Telefunken Patent | Electromechanical filter |
US3931600A (en) * | 1973-06-11 | 1976-01-06 | Kokusai Electric Co., Ltd. | Mechanical filter |
US4241321A (en) * | 1978-02-15 | 1980-12-23 | Fujitsu Limited | Electromechanical filter |
US4349903A (en) * | 1979-02-02 | 1982-09-14 | Licentia Patent-Verwaltungs-G.M.B.H. | Switching of channels between two premodulation systems |
Also Published As
Publication number | Publication date |
---|---|
IT616267A (en) | |
US3086182A (en) | 1963-04-16 |
NL233996A (en) | |
CH358874A (en) | 1961-12-15 |
NL113914C (en) | |
NL114041C (en) | |
GB842756A (en) | 1960-07-27 |
NL221977A (en) | |
FR1184459A (en) | 1959-07-22 |
CH353096A (en) | 1961-03-31 |
GB892922A (en) | 1962-04-04 |
SE178175C1 (en) | 1962-02-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3321648A (en) | Piezoelectric filter element | |
US3015789A (en) | Mechanical filter | |
US3585537A (en) | Electric wave filters | |
US2662217A (en) | Multiple-neck filter | |
US2994047A (en) | Mechanical filter coupling | |
US3185943A (en) | One-piece mechanical filter having portions forming plural resonators and coupling means | |
US2345491A (en) | Wave transmission network | |
US2615981A (en) | Electromechanical filter | |
US2828470A (en) | Tapped torsional delay lines | |
US3838366A (en) | Monolithic electro-mechanical filters | |
US3135933A (en) | M derived mechanical filter | |
US2738467A (en) | Mechanical resonator coupling utilizing poisson's effect | |
US2342869A (en) | Wave filter | |
US3013228A (en) | Mechanical frequency filter | |
US2091250A (en) | Wave filter | |
US3596212A (en) | Electrical band-pass filter employing monolithic crystals | |
US2969511A (en) | Mechanical high frequency filters | |
US3577180A (en) | Electromechanical filter | |
JPS6160612B2 (en) | ||
US1781513A (en) | Electrical tuning fork | |
US2511029A (en) | Dipole antenna system | |
US3028564A (en) | Mechanical filter | |
GB1074292A (en) | Improvements in or relating to electromechanical filters | |
US2303375A (en) | Rochelle salt piezoelectric crystal apparatus | |
US4100506A (en) | Electromechanical filter |