WO2001010057A1 - Schaltung zum umschalten zwischen empfangsantennen - Google Patents
Schaltung zum umschalten zwischen empfangsantennen Download PDFInfo
- Publication number
- WO2001010057A1 WO2001010057A1 PCT/DE2000/002370 DE0002370W WO0110057A1 WO 2001010057 A1 WO2001010057 A1 WO 2001010057A1 DE 0002370 W DE0002370 W DE 0002370W WO 0110057 A1 WO0110057 A1 WO 0110057A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- antenna
- antennas
- switching
- signal
- circuit according
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/44—Transmit/receive switching
- H04B1/48—Transmit/receive switching in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0805—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching
- H04B7/0814—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching based on current reception conditions, e.g. switching to different antenna when signal level is below threshold
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0825—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with main and with auxiliary or diversity antennas
Definitions
- the invention relates to a circuit for switching between the frequency-modulated RF signals from at least two receiver antennas according to the preamble of claim 1.
- a circuit which is based on the formulation of the preamble of claim 1, is known from DE-OS 35 17 247 ⁇ .
- This document describes an antenna diversity system for. describes the mobile reception of frequency-modulated RF signals, in which the essential diversity functions are integrated in a processor. The processor switches from one antenna to the next if it detects a disturbance in the audio signal while the level of the RF signal fluctuates.
- a threshold switch is used, which Diversity processor when falling below a predetermined reception level on the currently switched-on antenna switches back to the main antenna.
- the control is carried out via the mode input of the processor, which is provided so that a fixed antenna can be switched on when AM is received.
- a second predetermined level is exceeded, which is higher than the first by a certain amount, the diversity function is switched on again.
- the invention is based on the object of developing a circuit for switching between the frequency-modulated RF signals from at least two receiving antennas in such a way that interference from too frequent switching or unnecessary switching to a fixed antenna is avoided.
- a detector is therefore provided which applies a signal to the control unit which switches over to a specific antenna (usually referred to as a fixed antenna) when none of the antennas provides a signal which exceeds the predetermined reception level.
- the advantage of the invention is that a switch back to the main antenna only takes place if there is no sufficiently large RF signal at any antenna to ensure interference-free reception. It is only in this case that it makes sense to switch to a fixed antenna, which is also not interference-free, in order to suppress the additional audible interference that occurs as a result of constant switching.
- the diversity function is only switched on again when the arrival tennensignal exceeds the level threshold for a predetermined time.
- the detector can evaluate the level-equivalent direct voltage from the demodulator of the antenna diversity circuit.
- This evaluation includes a threshold switch that detects when the antenna falls below a specified level. It is preceded by a time delay. This ensures that the system does not switch to a fixed antenna until the level falls below the threshold for a period of time that corresponds at least to the time it takes the processor to scan all connected antennas.
- the time delay can be implemented, for example, as an integrator.
- the simplest case is a low-pass filter, the threshold switch being formed by an operational amplifier connected as a comparator.
- a further comparator can be connected upstream of the integrator. This ensures that the integration only begins when the threshold is actually fallen below. If the integrator is connected directly to the level output of the demodulator, this has the disadvantage that the delay time depends on the size of the voltage jump. If the level-equivalent voltage is slowly approaching the threshold value, this time is particularly short because the capacitor of the integra- tion member is almost to the specified threshold on charging.
- the detector evaluates the switching speed of the diversity processor. For this purpose, the control output connections of the processor are monitored. If a certain number of switching operations are triggered within a predetermined time, the system switches to a fixed antenna.
- the detector it is possible to connect the detector to only one control output connection of the diversity processor. Since the diversity processor always switches the antennas on and off one after the other in the same order, this is sufficient to determine the switching frequency and thus a criterion for switching to a fixed antenna.
- the main antenna (AM + FM) is used as the fixed antenna.
- the diversity processor has a mode input, via which it can be switched to the main antenna by a DC voltage with AM reception. This switchover option is also used if interference-free reception is no longer possible with any of the connected antennas.
- the fixed antenna that is switched to is the antenna with the best reception. To the- To determine this, it must be detected which antenna was switched on the longest during the last run.
- a memory element is connected to each control output terminal of the processor; in the simplest case, this is a charging capacitor. This memory element is overwritten each time it is run. If you want to switch to the fixed antenna, the memories are compared and the antenna that has been switched on for the longest time is used as the fixed antenna. To connect any antenna, the diversity processor must be switched off and the control line for the corresponding antenna must be connected to the supply voltage become.
- Fig. 1 is a
- Fig. 2 shows a modification of the embodiment.
- FIG. 1 shows a block diagram of a circuit with level jump-independent antenna level detection and with switching back to the main antenna.
- antennas 8, S, - ⁇ 10 and 11 are used without limiting the general applicability.
- the- Tenne 8 is a main antenna suitable for AM and FM reception, while antennas 9, 10 and 11 are only designed for FM reception.
- the antenna 8, 9, 10 or 11 that is currently switched on via a switching network 7 is demodulated in a demodulator 2 of the antenna diversity circuit.
- the audio signal and the level-equivalent direct voltage (level) from the demodulator are fed to a diversity processor 6. This provides the information when it is necessary to switch to the next antenna. It controls the switching network 7, which connects the antennas ⁇ , 9, 10 or 11.
- the level-proportional DC voltage is also fed to a comparator 3. If the level falls below a certain level, it switches to “HighV. It is followed by a low-pass filter 4, which acts as an integrator. The integrator 4 determines with its time constant how long the level must be below the threshold, bi3 a second threshold value is reached, so that a second comparator 5 goes to "high". This controls the processor mode. If the level falls below the threshold for a predetermined value The processor 6 is permanently switched to the main antenna 8.
- the processor 8 switches continuously between the antennas in the event of a weak reception, at which switching noises are only heard. If the antenna signal on the main antenna exceeds the threshold for If the set time period is exceeded again, the processor is switched back to scan-in mode.
- FIG. 2 shows the block diagram of a switching speed detection at a control output connection with switching to the antenna with the best reception.
- the same parts as in Fig. 1 are denoted by the same reference numerals.
- the RF signal of the current antenna 8, 9, 10 or 11 processed in the FM tuner and IF amplifier of the receiver 1 is demodulated in the demodulator 2 of the antenna diversity circuit.
- the audio signal and the level-equivalent direct voltage (level) from the demodulator are fed to the diversity processor 6. This provides the information when it is necessary to switch to the next antenna. It controls on / off switches 12 to 15.
- the changeover switch 7 is controlled by 'the evaluation circuit 17, which reads out the memory 15 and detects which antenna has been switched on the last run the longest.
- the diversity processor ⁇ is therefore switched off and switched on the last longest connected antenna via the switch 7.
- the changeover switch 18 is equipped with a timer, which leads to the processor being switched on again after a predetermined time in order to check whether the reception conditions have improved in the meantime.
- This variant also ensures that a fixed antenna is only selected when there is no interference-free signal on any connected antenna, because the switchover takes place only when the processor switches very frequently between the antennas.
- the switchover criterion is derived from the IF level.
- the evaluation of this value. is particularly simple because the demodulator in the diversity module supplies a level-equivalent DC voltage. A time delay is switched in front of the actual threshold switch so that all antennas are queried before switching to a fixed antenna.
- time delay is implemented as an integrator, in the simplest case a low-pass filter is, and the Schwellwert ⁇ chalter by an operational amplifier connected as a comparator, since these components are inexpensive and easy to implement.
- a further advantage is obtained if a further comparator is connected upstream of the integrator, so that the integration only begins when the threshold value has actually been fallen below. This ensures that the delay time is independent of the voltage jump of the level-equivalent DC voltage.
- the switching frequency is used as the switching criterion. This can rule out that the fixed antenna is switched on when the level is low, although the processor is not yet constantly switching.
- a further advantage is obtained if, instead of evaluating all control outputs, only one control output is evaluated with regard to the switching frequency, since this considerably reduces the outlay on circuitry. This is possible because the diversity processor (in all practical versions) always switches the antennas on and off in the same order.
- the main antenna is used as a fixed antenna, since this can be controlled very easily via the mode input of the diversity processor.
- the antenna with the best reception is used as a fixed antenna. To do this, it must be determined which antenna has been switched on the longest during the last run.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001513836A JP2003506916A (ja) | 1999-07-29 | 2000-07-21 | 受信アンテナ間の切替用のスイッチ |
US10/049,218 US6731921B1 (en) | 1999-07-29 | 2000-07-21 | Circuit for changing over between receiving antennas |
EP00956091A EP1205039A1 (de) | 1999-07-29 | 2000-07-21 | Schaltung zum umschalten zwischen empfangsantennen |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19935675A DE19935675A1 (de) | 1999-07-29 | 1999-07-29 | Schaltung zum Umschalten zwischen Empfangsantennen |
DE19935675.0 | 1999-07-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2001010057A1 true WO2001010057A1 (de) | 2001-02-08 |
Family
ID=7916496
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE2000/002370 WO2001010057A1 (de) | 1999-07-29 | 2000-07-21 | Schaltung zum umschalten zwischen empfangsantennen |
Country Status (6)
Country | Link |
---|---|
US (1) | US6731921B1 (de) |
EP (1) | EP1205039A1 (de) |
JP (1) | JP2003506916A (de) |
KR (1) | KR100808396B1 (de) |
DE (1) | DE19935675A1 (de) |
WO (1) | WO2001010057A1 (de) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009246961A (ja) * | 2002-04-05 | 2009-10-22 | Qualcomm Inc | 移動局において受信ダイバーシティを決定するための方法及び装置 |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10161271A1 (de) * | 2001-12-13 | 2003-07-03 | Harman Becker Automotive Sys | Verfahren zur Auswahl einer von mehreren Antennen einer Antennendiversity-Empfangsanlage und Antennendiversity-Empfangsanlage |
FI116248B (fi) * | 2003-02-14 | 2005-10-14 | Flextronics Odm Luxembourg Sa | Antennijärjestely ja kannettava päätelaite |
DE102006039357B4 (de) * | 2005-09-12 | 2018-06-28 | Heinz Lindenmeier | Antennendiversityanlage zum Funkempfang für Fahrzeuge |
JP2007258819A (ja) * | 2006-03-20 | 2007-10-04 | Casio Comput Co Ltd | Ofdm受信装置、ofdm受信方法及び地上波デジタル受信装置 |
US8194809B2 (en) * | 2006-03-28 | 2012-06-05 | Panasonic Corporation | Diversity receiver and diversity receiving method |
JP4692761B2 (ja) * | 2006-03-29 | 2011-06-01 | カシオ計算機株式会社 | Ofdm受信装置、ofdm受信方法及び地上波デジタル受信装置 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3641109A1 (de) * | 1986-12-02 | 1988-08-25 | Lindenmeier Heinz | Signaldiversity-anlage fuer den mobilen empfang |
DE4403612A1 (de) * | 1994-02-05 | 1995-08-10 | Lindenmeier Heinz | Schaltungsanordnung für ein Mehrantennen-Scanning-Diversitysystem |
DE8916287U1 (de) * | 1989-11-23 | 1997-08-21 | Fuba Automotive Gmbh | Schaltung zum Umschalten zwischen den frequenzmodulierten HF-Signalen von mindestens zwei Empfangsantennen |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4549311A (en) * | 1982-08-03 | 1985-10-22 | Motorola, Inc. | Method and apparatus for measuring the strength of a radio signal frequency |
US4499606A (en) * | 1982-12-27 | 1985-02-12 | Sri International | Reception enhancement in mobile FM broadcast receivers and the like |
JPS59181732A (ja) * | 1983-03-31 | 1984-10-16 | Toshiba Corp | 携帯用無線機におけるダイバ−シチ−受信方式 |
DE3517247A1 (de) * | 1985-05-13 | 1986-11-13 | Gerhard Prof. Dr.-Ing. 8012 Ottobrunn Flachenecker | Antennendiversity-empfangsanlage zur elimination von empfangsstoerungen |
NO175659C (no) * | 1988-07-06 | 1994-11-09 | Sumitomo Electric Industries | Kommunikasjonssystem med multippelmottagning og mottagerapparat for diversitetssignaler |
SE465991B (sv) * | 1990-04-10 | 1991-11-25 | Ericsson Telefon Ab L M | Foerfarande foer att i en mottagare vaelja den laempligaste av tvaa eller flera antenner |
US5561673A (en) * | 1993-04-16 | 1996-10-01 | Matsushita Electric Industrial Co., Ltd. | Antenna switched diversity reciever |
JPH09507371A (ja) * | 1994-10-17 | 1997-07-22 | フィリップス エレクトロニクス ネムローゼ フェンノートシャップ | ワイヤレスデジタル通信システム、無線装置、デジタルスピーカ及びデジタルスピーカ制御装置 |
DE19607045A1 (de) * | 1996-02-24 | 1997-08-28 | Lindenmeier Heinz | Empfangsantennen-Scanningdiversitysystem für den Meterwellenbereich für Fahrzeuge |
JP2959499B2 (ja) * | 1996-11-29 | 1999-10-06 | 日本電気株式会社 | 無線通信装置 |
JPH118577A (ja) * | 1997-06-17 | 1999-01-12 | Saitama Nippon Denki Kk | 無線機 |
US5940454A (en) * | 1997-12-17 | 1999-08-17 | Nortel Networks Corporation | Blind switch diversity control apparatus |
-
1999
- 1999-07-29 DE DE19935675A patent/DE19935675A1/de not_active Ceased
-
2000
- 2000-07-21 JP JP2001513836A patent/JP2003506916A/ja not_active Withdrawn
- 2000-07-21 WO PCT/DE2000/002370 patent/WO2001010057A1/de not_active Application Discontinuation
- 2000-07-21 EP EP00956091A patent/EP1205039A1/de not_active Ceased
- 2000-07-21 US US10/049,218 patent/US6731921B1/en not_active Expired - Fee Related
- 2000-07-21 KR KR1020017016778A patent/KR100808396B1/ko not_active IP Right Cessation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3641109A1 (de) * | 1986-12-02 | 1988-08-25 | Lindenmeier Heinz | Signaldiversity-anlage fuer den mobilen empfang |
DE8916287U1 (de) * | 1989-11-23 | 1997-08-21 | Fuba Automotive Gmbh | Schaltung zum Umschalten zwischen den frequenzmodulierten HF-Signalen von mindestens zwei Empfangsantennen |
DE4403612A1 (de) * | 1994-02-05 | 1995-08-10 | Lindenmeier Heinz | Schaltungsanordnung für ein Mehrantennen-Scanning-Diversitysystem |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009246961A (ja) * | 2002-04-05 | 2009-10-22 | Qualcomm Inc | 移動局において受信ダイバーシティを決定するための方法及び装置 |
Also Published As
Publication number | Publication date |
---|---|
KR100808396B1 (ko) | 2008-02-29 |
DE19935675A1 (de) | 2001-02-15 |
JP2003506916A (ja) | 2003-02-18 |
EP1205039A1 (de) | 2002-05-15 |
US6731921B1 (en) | 2004-05-04 |
KR20020012297A (ko) | 2002-02-15 |
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