EP0269924B1 - Kompensationsverstärker für eine Autoantenne - Google Patents

Kompensationsverstärker für eine Autoantenne Download PDF

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Publication number
EP0269924B1
EP0269924B1 EP19870116690 EP87116690A EP0269924B1 EP 0269924 B1 EP0269924 B1 EP 0269924B1 EP 19870116690 EP19870116690 EP 19870116690 EP 87116690 A EP87116690 A EP 87116690A EP 0269924 B1 EP0269924 B1 EP 0269924B1
Authority
EP
European Patent Office
Prior art keywords
band
pass filter
coil
tuning circuit
compensation amplifier
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.)
Revoked
Application number
EP19870116690
Other languages
English (en)
French (fr)
Other versions
EP0269924A2 (de
EP0269924A3 (en
Inventor
Kazuhiko Nakase
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.)
Harada Industry Co Ltd
Original Assignee
Harada Industry Co Ltd
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
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Application filed by Harada Industry Co Ltd filed Critical Harada Industry Co Ltd
Publication of EP0269924A2 publication Critical patent/EP0269924A2/de
Publication of EP0269924A3 publication Critical patent/EP0269924A3/en
Application granted granted Critical
Publication of EP0269924B1 publication Critical patent/EP0269924B1/de
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/1271—Supports; Mounting means for mounting on windscreens
    • H01Q1/1278—Supports; Mounting means for mounting on windscreens in association with heating wires or layers

Definitions

  • the present intention relates to a compensation amplifier for an automobile antenna utilizing, as an antenna element, a heating element for removing fog from an automobile rear window, said compensation amplifier comprising: an AM band-pass section with an AM band-pass filter coil connected to the heating element, for passing an amplitude-modulation radio signal; an FM band-pass section comprising a double tuning circuit having a primary and a secondary tuning circuit with an FM band-pass filter coil connected to the heating element, for passing a frequency-modulation radio signal; and a power source (B) being connected to the heating element through AM band-pass filter section and FM band-pass filter section.
  • the heating wire for removing fog formed on the rear window of an automobile has come to be used also as an antenna element for a radio receiver.
  • An example of this type of antenna is disclosed in Japanese Patent Disclosure (Kokai) No. 52-64,257 which corresponds to U.S. Patent No. 4,086,594 and U.K. Patent No. 1,520,030.
  • Fig. 1 shows this prior art.
  • Heating wire H is incorporated in the rear window of an automobile.
  • a blocking circuit made up of radio signal blocking coil 9 and choke coil 7 for suppressing interference are interposed between heating wire H and automobile battery B.
  • the radio signal such as a radio broadcasting signal, is picked up between heating wire H and blocking coil 9, and is amplified by preamplifier 13.
  • the output signal from preamplifier 13 is supplied to a radio receiver circuit (not shown) via feeder line 2.
  • Filtering capacitor 8, for removing noises from battery B is connected between choke coil 7 and a ground potential terminal. Choke coil 7, blocking coil 9, filtering capacitor 8, and preamplifier 13 together form compensation amplifier 1.
  • Heater on/off switch 3 is connected between choke coil 7 and battery B.
  • the inductance of blocking coil 9 is set at about 2 mH. Accordingly, the high frequency radio signal received by heating wire H, which is used as an antenna element, does not flow to the ground potential terminal but is instead transmitted to the radio receiver circuit via preamplifier 13 and feeder line 2. Blocking coil 9 is wound on a pot core which does not have air gaps.
  • heating wire H Since the direct current flowing through heating wire H is about 10 A, the heating wire is required to be relatively thick in order to permit this large direct current to flow therethrough. Accordingly, the size of blocking coil 9 must be large enough to ensure that the necessary inductance can be obtained, which results in the undesirable enlargement of the overall size of compensation amplifier 1.
  • the pot core is used in order to render the overall size of the automobile antenna amplifier as small as possible.
  • use of a pot core is expensive, and a surface of the pot core must be grinded to a mirror finish in order to eliminate air gaps. The necessity to do this increases the manufacturing cost of the automobile antenna.
  • AU-B-542 835 discloses a similar prior art, wherein, however, said blocking coil can be replaced by a tuned circuit formed of a coil and a variable capacitor connected in parallel. Tuned circuit allows passage of the D.C. signal but isolates the RF signal from the power supply.
  • a compensation amplifier of the above-mentioned type is disclosed by EP-A-0 146 339.
  • a coil arrangement of two serially connected coils is designed to block radio frequencies from the power source. FM signals are completely blocked by the coil arrangement and fed to the FM band-pass section whereas AM signal pass the first of said two coils and are fed to the AM band-pass section connected to the junction between said two coils. Therefore, this arrangement suffers from the problem of blocking coils as described above.
  • the object of the present invention is to provide a compensation amplifier for an automobile antenna utilizing a heating wire as an antenna element, which is small in size, has a low manufacturing cost, and reduces loss of signal.
  • a compensation amplifier of the above-mentioned type is characterized in that said AM band-pass section comprises a double tuning circuit having a primary tuning circuit and a secondary tuning circuit, the primary tuning circuit being formed of the AM band-pass filter coil and a capacitor connected between said heating element and a terminal of the power source; and by said FM band-pass filter double tuning circuit having the primary tuning circuit formed of the FM band-pass filter coil and the capacitor.
  • Fig. 2 is a circuit diagram of an embodiment of the compensation amplifier for an automobile antenna according to this invention.
  • This embodiment has coils interposed between heating wire H and DC (direct current) battery B, like the prior art.
  • these coils are not used for blocking the high frequency signal; in other words, these coils are not used as choke coils. Instead, these coils are used as a part of a band-pass filter, and this is the difference between this invention and the prior art.
  • Band-pass filter coil La1 for an AM (amplitude-modulation) signal, cancelling coil Lc which cancels out DC magnetization caused by AM band-pass filter coil La1, and band-pass filter coil Lf1 for an FM (frequency modulation) signal are connected between heating wire H and battery B.
  • FM band-pass filter coil Lf1 and AM band-pass filter coil La1 are wound on a toroidal core with air gaps.
  • An inductance of AM band-pass filter coil La1 is set at 1 mH or less.
  • Feed-through capacitor C for removing noises from battery B is interposed between cancelling coil Lc and battery B.
  • Heater on/off switch 3 is connected between feed-through capacitor C and battery B.
  • Capacitor Cs is connected between heating wire H and a ground potential terminal.
  • Coupling capacitor Co is connected between cancelling coil Lc and AM band-pass filter coil La1.
  • the FM signal is supplied to an FM signal preamplifier including bipolar transistor TR through an FM signal compensation circuit including coupling capacitor Cc, coil Lf2, capacitor CE, and resistor Rf.
  • Band-pass filter coil Lf1 and capacitor Cs are used as a part of an input band-pass filter for an FM signal compensation circuit.
  • an AM signal is supplied to an AM signal preamplifier including field-effect transistor FET through an AM signal compensation circuit including additional capacitor Cb, coil La2, capacitor Ca, and resistors Ra1 and Ra2.
  • AM signal compensation circuit including additional capacitor Cb, coil La2, capacitor Ca, and resistors Ra1 and Ra2.
  • Band-pass filter coil La1, capacitor Cs, and additional capacitor Cb are used as a part of an input band-pass filter for an AM signal compensation circuit.
  • Additional capacitor Cb tunes a frequency of an AM signal.
  • Fig. 3 shows an equivalent circuit diagram of the FM signal compensation circuit.
  • Ra is an antenna resistor.
  • This FM signal compensation circuit is a double tuning circuit and includes a primary tuning circuit and a secondary tuning circuit.
  • the primary tuning circuit is made up of FM band-pass filter coil Lf1 of an air-core type and capacitor Cs.
  • the secondary tuning circuit is made up of coil Lf2 and capacitor Cf.
  • capacitor Cs caused losses of the FM signal.
  • capacitor Cs since capacitor Cs is used as a part of the band-pass filter for tuning the FM signal, losses are not generated from capacitor Cs. Further, the gain of FM band can be increased by several dB's (Decibels) when compared with the prior art, due to the band-pass filter.
  • Fig. 4 shows an equivalent circuit diagram of the AM signal compensation circuit.
  • the AM signal compensation circuit is a double tuning circuit and includes a primary tuning circuit and a secondary tuning circuit.
  • the primary tuning circuit is a high-pass filter and includes AM band-pass filter coil La1 which is of an air-core type, capacitor Cs, and tuning capacitor Cb.
  • the secondary tuning circuit is a low-pass filter and includes coil La2 and capacitor Ca.
  • the capacitor Cs is used as a part of the band-pass filter for the AM band, losses are not generated from capacitor Cs. Further, the gain of the AM band can be increased by several dB's when compared with the prior art.
  • Figs. 5A and 5B show examples of windings of AM band-pass filter coil La1 and cancelling coil Lc.
  • AM band-pass filter coil La1 and cancelling coil Lc are wound on ferrite core F as a bifilar winding. In the example of Fig. 5B, they are wound separately.
  • band-pass filter coil La1 is used as a part of a band-pass filter and not as a choke coil. Accordingly, it does not matter that high frequency signal received by the heating wire, which is used as an antenna element, flows into the ground potential terminal.
  • the inductance of coil 9 is set large so that the radio signal does not flow into the ground.
  • the coil is used as the coil alone, it works as a choke coil and blocks the signal to flow.
  • the coil is used as a tuning circuit with the capacitor, it permits to flow the signal of a tuned frequency range.
  • the present invention it is not necessary to set the inductance value of the band-pass filter as high as in the prior art.
  • a toroidal core rather than a pot core can be used in this invention.
  • the device can be manufactured at a lower cost than the prior art.
  • both AM and FM coils can be small in size, the overall size of the entire device can be also small.
  • the feed-through capacitor C inhibits the power supply noise caused by battery B from entering into the AM or FM compensation circuit.
  • Additional capacitor Cb, together with band-pass filter coil La1 not only comprises a band-pass filter for an AM signal but also functions as a by-pass capacitor for an FM signal.
  • a stable tuning characteristic for an FM signal is obtainable without getting any influence from the AM compensation circuit.
  • the core used in the above embodiment for the windings of band-pass filter coil La1 and cancelling coil Lc is not limited to the torodidal core, and the pot core can be also used. With the use of the pot core, the size of the entire device can be further reduced.
  • the overall size of the compensation amplifier for the automobile antenna can be reduced, and this is advantageous in view of the lower cost of manufacturing the same.

Landscapes

  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Details Of Aerials (AREA)
  • Amplifiers (AREA)

Claims (6)

  1. Kompensationsvertärker für eine Autoantenne, die als Antennenelement ein Heizelement (H) zum Entfernen von Beschlag von einer Autoheckscheibe verwendet, wobei der Kompensationsverstärker aufweist:
    - einen AM-Bandpaßteil mit einer mit dem Heizelement verbundenen Bandpaßfilterspule zum Durchlassen eines ämplitudenmodulierten Radiosignals;
    - einem FM-Bandpaßteil, der eine Doppel-Abstimmschaltung mit einem ersten und einem zweiten Abstimmkreis aufweist, mit einer mit dem Heizelement verbundenen FM-Bandpaßfilterspule zum Durchlassen eines frequenzmodulierten Radiosignals; und
    - einer über den AM-Bandpaßfilterteil und den FM-Bandpaßfilterteil mit dem Heizelement verbundenen Stromquelle (B),
    dadurch gekennzeichnet, daß
    der AM-Bandpaßteil eine Doppelastimmschaltung mit einem ersten Abstimmkreis und einem zweiten Abstimmkreis aufweist, wobei der erste Abstimmkreis aus einer zwischen das Heizelement (H) und einem Anschluß der Stromquelle (B) geschalteten AM-Bandpaßfilterspule (La1) und einer Kapazität (Cs) gebildet ist, und
    daß der erste Abstimmkreis der Doppelabstimmschaltung des FM-Bandpaßteils aus einer FM-Bandpaßfilterspule (Lf1) und der Kapazität (Sf) besteht.
  2. Kompensationsvertärker nach Anspruch 1, gekennzeichnet durch eine Kompensationsspule (Lc), die parallel zu der AM-Bandpaßfilterspule (La1) zum Auslöschen einer Gleichstrommagnetisierung geschaltet ist, die durch einen Gleichstromfluß durch die AM-Bandpaßfilterpsule (La1) entstanden ist.
  3. Kompensationsverstärker nach Anspruch 2, dadurch gekennzeichnet, daß die AM-Bandpaßfilterspule (La1) und die Kompensationsspule (Lc) als bifilare Wicklung auf eine Pyritkern (F) gewickelt sind.
  4. Kompensationsverstärker nach Anspruch 2, dadurch gekennzeichnet, daß die AM-Bandpaßfilterspule (La1) und die Kompensationsspule (Lc) separat auf einen Pyritkern (F) gewickelt sind.
  5. Kompensationsverstärker nach Anspruch 3 oder 4, dadurch gekennzeichnet, daß der Pyritkern (F) ein Toroidkern mit einem Luftspalt ist.
  6. Kompensationsverstärker nach Anspruch 2, dadurch gekennzeichnet, daß die AM-Bandpaßfilterspule (La1) mit der Kompensationsspule (Lc) über einen Koppelkondensator (Co) verbunden ist.
EP19870116690 1986-11-21 1987-11-12 Kompensationsverstärker für eine Autoantenne Revoked EP0269924B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP278211/86 1986-11-21
JP27821186A JPS63131704A (ja) 1986-11-21 1986-11-21 ガラスアンテナの補償増幅装置

Publications (3)

Publication Number Publication Date
EP0269924A2 EP0269924A2 (de) 1988-06-08
EP0269924A3 EP0269924A3 (en) 1989-12-27
EP0269924B1 true EP0269924B1 (de) 1994-01-26

Family

ID=17594145

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870116690 Revoked EP0269924B1 (de) 1986-11-21 1987-11-12 Kompensationsverstärker für eine Autoantenne

Country Status (4)

Country Link
EP (1) EP0269924B1 (de)
JP (1) JPS63131704A (de)
AU (1) AU586938B2 (de)
DE (1) DE3788938T2 (de)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0346089B1 (de) * 1988-06-10 1993-09-29 Nippon Sheet Glass Co., Ltd. Empfangssystem
JPH0453070Y2 (de) * 1988-06-10 1992-12-14
EP0629018A3 (de) * 1988-07-14 1995-06-14 Asahi Glass Co Ltd Kraftfahrzeugantenne.
JPH0232625A (ja) * 1988-07-22 1990-02-02 Pioneer Electron Corp アンテナブースタ回路
JPH0262813U (de) * 1988-10-31 1990-05-10
US5113195A (en) * 1988-10-31 1992-05-12 Nippon Sheet Glass Co., Ltd. Glass window antenna for use in a motor vehicle
JPH0722892Y2 (ja) * 1988-11-22 1995-05-24 日本板硝子株式会社 自動車用受信装置
GB8916524D0 (en) * 1989-07-19 1989-09-06 Bsh Electronics Ltd Signal separating device
JPH03103619U (de) * 1990-02-08 1991-10-28
GB9207620D0 (en) * 1992-04-08 1992-05-27 Glass Antennas Tech Ltd Coil construction
US5835066A (en) * 1992-04-08 1998-11-10 Glass Antennas Technology Limited Coil construction
GB2295729B (en) * 1992-04-08 1996-09-25 Glass Antennas Tech Ltd Coil construction
DE69427506T2 (de) * 1993-08-20 2001-10-04 Asahi Glass Co Ltd Scheibenantenne für ein Automobil
US11109451B2 (en) * 2016-07-20 2021-08-31 Kymeta Corporation Internal heater for RF apertures

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3939423A (en) * 1974-07-01 1976-02-17 Viktor Ivanovich Zakharov Automobile active receiving antenna
GB1520030A (en) * 1975-11-21 1978-08-02 Bsh Electronics Manchester Ltd Electrical device to enable the heating element of an electrically heated motor vehicle window to be used as a radio aerial
JPS52131934U (de) * 1976-04-01 1977-10-06
JPS5840451Y2 (ja) * 1980-09-24 1983-09-12 十和田観光電鉄株式会社 運賃箱における紙葉類の強制落下装置
EP0146339B1 (de) * 1983-12-20 1989-09-13 Bsh Electronics Limited Trennungsvorrichtung für elektrisches Signal mit Isolierungs- und Anpassungsschaltung
AU591909B2 (en) * 1986-06-24 1989-12-21 Bsh Electronics Limited Signal separating device

Also Published As

Publication number Publication date
EP0269924A2 (de) 1988-06-08
DE3788938T2 (de) 1994-05-05
EP0269924A3 (en) 1989-12-27
AU586938B2 (en) 1989-07-27
JPH0445019B2 (de) 1992-07-23
DE3788938D1 (de) 1994-03-10
AU8097787A (en) 1988-06-09
JPS63131704A (ja) 1988-06-03

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