WO1992009145A1 - Method of operating a car radio - Google Patents

Method of operating a car radio Download PDF

Info

Publication number
WO1992009145A1
WO1992009145A1 PCT/EP1991/001983 EP9101983W WO9209145A1 WO 1992009145 A1 WO1992009145 A1 WO 1992009145A1 EP 9101983 W EP9101983 W EP 9101983W WO 9209145 A1 WO9209145 A1 WO 9209145A1
Authority
WO
WIPO (PCT)
Prior art keywords
radio
facility
operating
khz
car radio
Prior art date
Application number
PCT/EP1991/001983
Other languages
French (fr)
Inventor
Herbert Brockhaus
Original Assignee
Audi Ag
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
Application filed by Audi Ag filed Critical Audi Ag
Publication of WO1992009145A1 publication Critical patent/WO1992009145A1/en

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
    • H04B1/06—Receivers
    • H04B1/16—Circuits

Definitions

  • the invention relates to a method of operating a car radio according to the preamble of claim 1.
  • Such car radios are prior art and cassette, tape and CD players are generally provided as the playback facility for pre-recorded sound carriers.
  • a common problem with car radios is interference, particularly the type of interference which occurs because of the operation of other electrical appliances in the motor vehicle. Particularly in the high-frequency range, such interference can distinctly affect listening enjoyment.
  • the aim of the invention is to reduce such interference. Said aim is achieved by the main claim.
  • the bandwidth, within which the acoustic frequencies are radiated is different when using the radio facility than when using the playback facility. This is based on the finding that especially interference in the range above 5 kHz is basically caused by the fact that other current-consuming appliances in the motor vehicle are radiating electromagnetic waves which are intercepted by the tuner of the car radio and are accordingly converted into audible sounds.
  • the audible frequency range in the case of the radio facility is preferably clipped at an upper value of at most 10 kHz, preferably 7 to 8 kHz, while endeavouring in the case of reproduction from pre-recorded sound carriers to retain the ability also to reproduce frequencies of 12 kHz or more.
  • the single drawing is a diagrammatic view of a car radio, which has a pre ⁇ amplifier 10, an output amplifier 12 and a loudspeaker 14.
  • Signals are supplied to the pre-amplifier 10, for example by way of the car aerial and a tuner, indicated by the reference numeral 16, and by way of a cassette player 20.
  • bandpass filters 16 and 22 which are associated with the signals from the tuner 16 and from the cassette tape player respectively.
  • the individual signals are switched to the input of the amplifier 12 by a switch 24.
  • a bandpass filter 18 Associated with the VHF tuner 16 is a bandpass filter 18 which has a lower pass-band width than the bandpass filter 22 associated with the cassette tape player 20.
  • the upper limit value of the passband for the tuner 16 is set at around 8 kHz while the upper l mit value of the passband for the signals from the cassette tape player 20 is around 16 kHz and is basically determined by the technically dictated bandwidth of the amplifier.
  • the signals in the range between 8 kHz and 16 kHz intercepted by the tuner during radio reception are clipped and this makes itself evident in an improved quality of reproduction because high-frequency interference is thereby eliminated.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)

Abstract

A car radio is proposed, in which high frequencies are tuned out while the radio is in operation but are transmitted when the sound reproduction facility is in operation. In this manner, higher-frequency interference irradiations are filtered out and suppressed when the radio is in operation.

Description

Method of operating a car radio
The invention relates to a method of operating a car radio according to the preamble of claim 1.
Such car radios are prior art and cassette, tape and CD players are generally provided as the playback facility for pre-recorded sound carriers.
A common problem with car radios is interference, particularly the type of interference which occurs because of the operation of other electrical appliances in the motor vehicle. Particularly in the high-frequency range, such interference can distinctly affect listening enjoyment.
The aim of the invention is to reduce such interference. Said aim is achieved by the main claim.
According to the invention, it is provided that the bandwidth, within which the acoustic frequencies are radiated, is different when using the radio facility than when using the playback facility. This is based on the finding that especially interference in the range above 5 kHz is basically caused by the fact that other current-consuming appliances in the motor vehicle are radiating electromagnetic waves which are intercepted by the tuner of the car radio and are accordingly converted into audible sounds.
The risk of said interference irradiations being received in other components of the car radio is greatly reduced so that preventive measures do not have to be taken to the same extent.
Thus, it is possible to restrict the bandwidth for reproduction of the audible frequencies during operation of the radio facility in the top frequency range, with this in no way being detrimental to clarity of the spoken word. Receiving hi-fi quality radio transmissions on the car radio is also only possible to a very limited extent because constant changes in location and shadowing lead in any case to changing reception conditions so that the quality of music reception is distinctly affected. Clipping higher frequencies during reproduction therefore entails no significant loss of quality, while the tuning-out of interference achieved thereby is extremely advantageous.
However, when listening to music - or also speech - on the reproduction unit for pre-recorded sound carriers, i.e. for example a cassette or compact disk player, a far better quality is possible because the changing reception properties no longer play any part. At the same time, when operating in said manner, the risk of interference irradiations is much less, so that there is no longer any need for arbitrary clipping of the frequency range in the range of audibility of high-pitched sounds. In this instance, the full range determined by the properties of the amplifier or pre-amplifier may be utilised.
The audible frequency range in the case of the radio facility is preferably clipped at an upper value of at most 10 kHz, preferably 7 to 8 kHz, while endeavouring in the case of reproduction from pre-recorded sound carriers to retain the ability also to reproduce frequencies of 12 kHz or more.
The invention is described below with reference to the drawing.
The single drawing is a diagrammatic view of a car radio, which has a pre¬ amplifier 10, an output amplifier 12 and a loudspeaker 14.
Signals are supplied to the pre-amplifier 10, for example by way of the car aerial and a tuner, indicated by the reference numeral 16, and by way of a cassette player 20. Provided in the pre-amplifier 10 are bandpass filters 16 and 22 which are associated with the signals from the tuner 16 and from the cassette tape player respectively. The individual signals are switched to the input of the amplifier 12 by a switch 24. Associated with the VHF tuner 16 is a bandpass filter 18 which has a lower pass-band width than the bandpass filter 22 associated with the cassette tape player 20. Whereas the lower limit value of the passband is identical both for the signals from the tuner 16 and for the signals from the cassette player 20, the upper limit value of the passband for the tuner 16 is set at around 8 kHz while the upper l mit value of the passband for the signals from the cassette tape player 20 is around 16 kHz and is basically determined by the technically dictated bandwidth of the amplifier. Thus, the signals in the range between 8 kHz and 16 kHz intercepted by the tuner during radio reception are clipped and this makes itself evident in an improved quality of reproduction because high-frequency interference is thereby eliminated.

Claims

PATENT CLAIMS
1. Method of operating a car radio with a radio receiving facility and a playback facility for pre-recorded sound carriers, and with an amplifier component having a bandwidth for reproduction of audible frequencies, characterised in that the bandwidth associated with the radio receiving facility is different to that associated with the playback facility.
2. Method according to claim 1, characterised in that the upper limit value of the bandwidth when operating the radio receiving facility is lower than the upper limit value when operating the playback facility.
3. Method according to claim 2, characterised in that an upper limit value of at most 10 kHz is associated with operation of the radio receiving facility and an upper limit value of at least 12 kHz is associated with operation of the playback facility.
PCT/EP1991/001983 1990-11-09 1991-10-18 Method of operating a car radio WO1992009145A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4035672.8 1990-11-09
DE19904035672 DE4035672A1 (en) 1990-11-09 1990-11-09 METHOD FOR OPERATING A CAR RADIO

Publications (1)

Publication Number Publication Date
WO1992009145A1 true WO1992009145A1 (en) 1992-05-29

Family

ID=6417950

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1991/001983 WO1992009145A1 (en) 1990-11-09 1991-10-18 Method of operating a car radio

Country Status (2)

Country Link
DE (1) DE4035672A1 (en)
WO (1) WO1992009145A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443038A (en) * 1962-02-01 1969-05-06 Fisher Radio Corp Recording system with signal return circuit for allowing the use of certain filters and amplifiers in both record and reproduce modes
DE3034937A1 (en) * 1979-09-17 1981-04-09 Nissan Motor Co., Ltd., Yokohama, Kanagawa CIRCUIT FOR AUTOMATIC NOISE REDUCTION IN A FM RECEIVER

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443038A (en) * 1962-02-01 1969-05-06 Fisher Radio Corp Recording system with signal return circuit for allowing the use of certain filters and amplifiers in both record and reproduce modes
DE3034937A1 (en) * 1979-09-17 1981-04-09 Nissan Motor Co., Ltd., Yokohama, Kanagawa CIRCUIT FOR AUTOMATIC NOISE REDUCTION IN A FM RECEIVER

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
GRUNDIG TECHNISCHE INFORMATION vol. 31, no. 1-2, 1984, REGENSBURG,DE pages 73 - 101; SINNING ET AL: 'WKC 2858 VD - Ein Vollstereo-4-Endstufen,Synthesizer-Autoradio mit Reverse-Laufwerk und Dolby-B-NR' see page 76, column 1, line 50 - page 76, column 2, line 1 *

Also Published As

Publication number Publication date
DE4035672A1 (en) 1992-05-14

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