CA2253660A1 - Communication system comprising at least two filter branches - Google Patents
Communication system comprising at least two filter branches Download PDFInfo
- Publication number
- CA2253660A1 CA2253660A1 CA002253660A CA2253660A CA2253660A1 CA 2253660 A1 CA2253660 A1 CA 2253660A1 CA 002253660 A CA002253660 A CA 002253660A CA 2253660 A CA2253660 A CA 2253660A CA 2253660 A1 CA2253660 A1 CA 2253660A1
- Authority
- CA
- Canada
- Prior art keywords
- filter
- signal
- communications system
- electro
- communication system
- 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.)
- Abandoned
Links
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
- H03H9/64—Filters using surface acoustic waves
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Transceivers (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
The invention concerns a communication system comprising at least two filter branches which each contain a surface wave filter (21, 22), electro-acoustic filter structures (23) being provided on a common piezoelectric substrate (20).
Description
CA 022~3660 1998-11-06 GR 96 P 1464 P - Foreign Version -~ ILE ~! T, '~S ~r~
Descrlptlon -'F~'i .:.~.''' Lr.~''~ .'' Communications system containing at least two filter branches The present invention relates to a communications system with at least two filter branches, each containing a filter operating with surface acousting waves - SAW filter.
Communications systems of the type in question can be designed in such a way that a reception signal of a particular frequency is converted to a predetermined intermediate frequency by means of a mixer. In this case, the mixer is driven by a signal with likewise specific frequency from a local oscillator. With this design, both the reception signal and the signal from the local oscillator need to be filtered before mixing.
An outline block circuit diagram of a communications system of this type, with two filter branches, is represented in Figure 3. In this case, a reception signal is fed into a filter 1 at an input 3, and a signal from a local oscillator is fed into a filter 2 at an input 4. The output signals of the two filters 1 and 2 are fed into a mixer 5, at whose output 6 an intermediate-frequency signal can be tapped.
Figure 4 shows a schematic representation of an SAW filter which can be used as filter 1 or 2 according to Figure 3. In this filter, an electro-acoustic filter structure 11 is provided on a piezoelectric substrate 10. The filter formed by the piezoelectric substrate 10 and the electro-acoustic structure 11 is arranged in a housing 12. By means of contact wires 16, a connection is made from the electro-acoustic structure 11 to a signal input 13, a signal output 14 and ground terminals 15.
CA 022~3660 1998-11-06 If the communications system in question is a mobile telephone system, then the space available for the required circuit components of the system is limited in wire-free portable telephone sets.
The object of the present invention is therefore to provide filters which need little space and can be used for communications systems.
In the case of a communications system of the type mentioned at the start, this object is achieved by the measures of the characterizing part of patent claim 1.
A development of the invention forms the subject-matter of subclaims.
The invention will be explained in more detail below with the aid of an illustrative embodiment according to Figures 1 and 2 of the drawing. In this case, Figures 1 and 2 show representations corresponding to the abovementioned representations according to Figures 3 and 4.
According to Figure 1, two SAW filters 21 and 22 are provided on a piezoelectric substrate 20, an electro-acoustic filter structure in the form of an interdigital structure 23 being schematically indicated in the filter 22. The multiple filter formed by the piezoelectric substrate 20 as well as the filters 21 and 22 is arranged in a single housing 24. Via contact wires 30, electrical connections are made to signal inputs 25, 26, signal outputs 27, 28 and to ground terminals 29.
A schematic block circuit diagram for a communications system with a multiple filter according to Figure 1 is represented in Figure 2 with a reception-signal input 30, an input 31 for a CA 022~3660 1998-11-06 signal from a local oscillator, a filter 32 combined to form a module for the two signals, a mixer 33 and an output 34 for an intermediate-frequency signal.
The combination or integration of filters on a single substrate in a single housing is not restricted to two filter structures according to Figure 1. If a plurality of signals of different frequency positions need to be filtered, then the various SAW filter structures can be produced on a single substrate in a single housing. The number of filter structures is thus not limited to two.
Descrlptlon -'F~'i .:.~.''' Lr.~''~ .'' Communications system containing at least two filter branches The present invention relates to a communications system with at least two filter branches, each containing a filter operating with surface acousting waves - SAW filter.
Communications systems of the type in question can be designed in such a way that a reception signal of a particular frequency is converted to a predetermined intermediate frequency by means of a mixer. In this case, the mixer is driven by a signal with likewise specific frequency from a local oscillator. With this design, both the reception signal and the signal from the local oscillator need to be filtered before mixing.
An outline block circuit diagram of a communications system of this type, with two filter branches, is represented in Figure 3. In this case, a reception signal is fed into a filter 1 at an input 3, and a signal from a local oscillator is fed into a filter 2 at an input 4. The output signals of the two filters 1 and 2 are fed into a mixer 5, at whose output 6 an intermediate-frequency signal can be tapped.
Figure 4 shows a schematic representation of an SAW filter which can be used as filter 1 or 2 according to Figure 3. In this filter, an electro-acoustic filter structure 11 is provided on a piezoelectric substrate 10. The filter formed by the piezoelectric substrate 10 and the electro-acoustic structure 11 is arranged in a housing 12. By means of contact wires 16, a connection is made from the electro-acoustic structure 11 to a signal input 13, a signal output 14 and ground terminals 15.
CA 022~3660 1998-11-06 If the communications system in question is a mobile telephone system, then the space available for the required circuit components of the system is limited in wire-free portable telephone sets.
The object of the present invention is therefore to provide filters which need little space and can be used for communications systems.
In the case of a communications system of the type mentioned at the start, this object is achieved by the measures of the characterizing part of patent claim 1.
A development of the invention forms the subject-matter of subclaims.
The invention will be explained in more detail below with the aid of an illustrative embodiment according to Figures 1 and 2 of the drawing. In this case, Figures 1 and 2 show representations corresponding to the abovementioned representations according to Figures 3 and 4.
According to Figure 1, two SAW filters 21 and 22 are provided on a piezoelectric substrate 20, an electro-acoustic filter structure in the form of an interdigital structure 23 being schematically indicated in the filter 22. The multiple filter formed by the piezoelectric substrate 20 as well as the filters 21 and 22 is arranged in a single housing 24. Via contact wires 30, electrical connections are made to signal inputs 25, 26, signal outputs 27, 28 and to ground terminals 29.
A schematic block circuit diagram for a communications system with a multiple filter according to Figure 1 is represented in Figure 2 with a reception-signal input 30, an input 31 for a CA 022~3660 1998-11-06 signal from a local oscillator, a filter 32 combined to form a module for the two signals, a mixer 33 and an output 34 for an intermediate-frequency signal.
The combination or integration of filters on a single substrate in a single housing is not restricted to two filter structures according to Figure 1. If a plurality of signals of different frequency positions need to be filtered, then the various SAW filter structures can be produced on a single substrate in a single housing. The number of filter structures is thus not limited to two.
Claims (4)
1. A communications system with at least two filter branches, each containing a filter operating with surface acoustic waves - SAW filter, characterized in that the electro-acoustic structures (23) of the filters (21, 22) are provided on a common piezoelectric substrate (20).
2. The communications system as claimed in claim 1, characterized in that the substrate (20) comprising the electro-acoustic structures is arranged in a single housing (24).
3. A circuit arrangement for a communications system as claimed in claim 1 or 2, characterized in that a reception-signal input (30) and an input (31) for a signal from a local oscillator are provided, in that the two signals are fed to a filter (32) combined to form a module, and in that a mixer (33) is provided, at whose output (34) there is an intermediate-frequency signal.
4. The use of a circuit arrangement as claimed in claim 3 in a mobile radio.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19618706A DE19618706A1 (en) | 1996-05-09 | 1996-05-09 | Communication system containing at least two filter branches |
| DE19618706.0 | 1996-05-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2253660A1 true CA2253660A1 (en) | 1997-11-20 |
Family
ID=7793857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002253660A Abandoned CA2253660A1 (en) | 1996-05-09 | 1997-04-25 | Communication system comprising at least two filter branches |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0897611B1 (en) |
| JP (1) | JP2000510301A (en) |
| KR (1) | KR20000010802A (en) |
| CN (1) | CN1218586A (en) |
| CA (1) | CA2253660A1 (en) |
| DE (2) | DE19618706A1 (en) |
| WO (1) | WO1997043827A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2346049A (en) | 1999-01-19 | 2000-07-26 | Roke Manor Research | Duplex filtering |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2609883A1 (en) * | 1975-03-11 | 1976-09-30 | Murata Manufacturing Co | Acoustic surface wave filter - has piezoelectric substrate with input and output transducer systems |
| JPS61142812A (en) * | 1984-12-17 | 1986-06-30 | Toshiba Corp | Surface acoustic wave filter |
| JPS62105514A (en) * | 1985-11-01 | 1987-05-16 | Kokusai Denshin Denwa Co Ltd <Kdd> | Surface acoustic wave filter bank |
| JPH07288484A (en) * | 1994-04-18 | 1995-10-31 | Nec Corp | Reception circuit having surface acoustic wave device |
-
1996
- 1996-05-09 DE DE19618706A patent/DE19618706A1/en not_active Withdrawn
-
1997
- 1997-04-25 WO PCT/DE1997/000843 patent/WO1997043827A1/en not_active Application Discontinuation
- 1997-04-25 KR KR1019980708936A patent/KR20000010802A/en not_active Application Discontinuation
- 1997-04-25 CA CA002253660A patent/CA2253660A1/en not_active Abandoned
- 1997-04-25 EP EP97922868A patent/EP0897611B1/en not_active Revoked
- 1997-04-25 DE DE59701319T patent/DE59701319D1/en not_active Expired - Fee Related
- 1997-04-25 CN CN97194486A patent/CN1218586A/en active Pending
- 1997-04-25 JP JP09540371A patent/JP2000510301A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| WO1997043827A1 (en) | 1997-11-20 |
| CN1218586A (en) | 1999-06-02 |
| EP0897611A1 (en) | 1999-02-24 |
| JP2000510301A (en) | 2000-08-08 |
| EP0897611B1 (en) | 2000-03-22 |
| DE59701319D1 (en) | 2000-04-27 |
| DE19618706A1 (en) | 1997-11-13 |
| KR20000010802A (en) | 2000-02-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |