EP0691050A1 - Circuit for deriving audio signal masking signals - Google Patents
Circuit for deriving audio signal masking signalsInfo
- Publication number
- EP0691050A1 EP0691050A1 EP94911062A EP94911062A EP0691050A1 EP 0691050 A1 EP0691050 A1 EP 0691050A1 EP 94911062 A EP94911062 A EP 94911062A EP 94911062 A EP94911062 A EP 94911062A EP 0691050 A1 EP0691050 A1 EP 0691050A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- signal
- signals
- masking
- circuit arrangement
- arrangement according
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H40/00—Arrangements specially adapted for receiving broadcast information
- H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
- H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
- H04H40/36—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving
- H04H40/45—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving
- H04H40/63—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving for separation improvements or adjustments
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H40/00—Arrangements specially adapted for receiving broadcast information
- H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
- H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
- H04H40/36—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving
- H04H40/45—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving
- H04H40/72—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving for noise suppression
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/53—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers
- H04H20/57—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers for mobile receivers
Definitions
- the reception quality can fluctuate significantly, particularly with car radios.
- measures for masking these interference in audio signals are known. For example, with low reception field strength, it is possible to reduce the stereo channel separation or to temporarily attenuate the audio signals.
- the object of the present invention is to provide a circuit arrangement for a radio receiver, in particular for a car radio with digital signal processing, with which circuitry suitable signals are generated for masking audio signals.
- This object is achieved in that a signal which is substantially proportional to the reception field strength is passed through a low-pass filter and then weighted with a predetermined function.
- the circuit arrangement according to the invention has the advantage that the generated signals to the one to be carried out Masking are adaptable, so that an intervention made by the masking in the audio signals causes as far as possible no further audible interference.
- Another advantageous embodiment consists in that the masking is carried out by reducing the stereo channel separation, the weighting being carried out by multiplication by a coefficient which is stored in a memory.
- coefficients can also be permanently stored in the circuit arrangement according to the invention, a further development of the invention is particularly advantageous in that the coefficient or coefficients are stored in a non-volatile memory and with the aid of a microcomputer, a display device and an operating device and with the aid of a program are changeable for operator guidance.
- a further improvement of the circuit arrangement according to the invention is possible by combining the weighted field strength signals to form masking signals with auxiliary signals which indicate the presence of interference signals.
- the combination with the auxiliary signals is preferably carried out by multiplication.
- 1 shows a first embodiment
- 2 shows a part of the exemplary embodiment in more detail
- Fig. 6 shows a second embodiment
- Fig. 7 essential parts of a radio receiver with a circuit arrangement according to the invention.
- Signal processing steps such as filtering or nonlinear weighting, are carried out by arithmetic operations.
- digital signal processors and other digital circuits such as shift registers, flip-flops etc., can also be arranged together within an integrated circuit.
- a signal H3 is fed to an input 1 which corresponds to the received field strength in is substantially proportional and is referred to below as auxiliary signal H3.
- auxiliary signal H3 This is experienced in two.
- Low pass filters 2, 3 are averaged with different time constants.
- a changeover switch 4 forwards one of the output signals of the low-pass filters 2, 3 as a signal AMC depending on a signal DD2 to be explained later. This is weighted at 5 to generate a signal AFE indicating the noise attenuation and can be removed at an output 6.
- the signal WF with a smaller time constant is also weighted at 7 and can be taken from an output 8 as signal WF2.
- Coefficients K1, K2 required for weighting are stored in a non-volatile memory 9 and are supplied to the circuits 5, 7 via a microcomputer 10.
- K1 and K2 can be individual coefficients or a group of coefficients.
- a display device 11 and an input device 12 are connected to the microcomputer 10.
- the microcomputer 10 is provided with a program which allows the setting of the coefficients in a menu-driven manner.
- Fig. 3 shows an example of a circuit 5 (Fig. 1), in which the signal AMC supplied at 23 with an am Input 24 applied coefficient K2 is multiplied by 25.
- the signal AFE can be taken from an output 26.
- both detectors 36, 37 are provided, the output signals AHD and ASD of which are routed via a controllable logic network 38.
- this has the advantage that, in the case of pure mono broadcasts in which no carrier-frequency stereo signal is transmitted, the signal DD2 is derived from the auxiliary signal H1. It is also possible to derive the DD2 signal using stereo signal transmission methods that deviate from the European standard - for example, the FMX method in the USA.
- the logical network 38 enables a selection or a logical combination of the two signals AHD and ASD to the signal DD1.
- the logical network 38 can be formed in a simple manner from a controllable four-way switch, the inputs of which are the signals AHD and ASD, an OR combination of these signals and an AND combination these signals can be fed.
- the signal DD1 is then available at the output of the controllable changeover switch and is fed to a pulse width discriminator 39. This ensures that the signal DD2 only indicates a fault when the signal DD1 is active for an adjustable minimum time.
- the signal DD2 serves as a trigger signal for two asymmetrical integrators 40, 41. These essentially each contain a counter which jumps to 0 or another predetermined value at the moment of triggering and retains it as long as the signal DD2 is at 0. If the signal DD2 then assumes the logic level 1, the output signals AT1 and AMU of the asymmetrical integrators 40, 41 increase linearly to a maximum value with adjustable time constants.
- the signal AT1 is fed to a multiplier 33 together with the field strength signal WF2 weighted at 32.
- the stereo multiplex signal MPX2 is then passed through a circuit 57 for automatic interference suppression, which repeats the sample values before the start of the interference, especially when spark interference occurs, until the end of the interference.
- This circuit is followed by a stereo decoder 58, which generates two audio signals L, R, which are passed to outputs 61, 62 via multipliers 59, 60. From there, the audio signals are fed to the loudspeakers via NF amplifiers.
- the auxiliary signal H2 whose sampling rate is also 9.5 kHz
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Noise Elimination (AREA)
- Stereo-Broadcasting Methods (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4309518 | 1993-03-24 | ||
DE4309518A DE4309518A1 (en) | 1993-03-24 | 1993-03-24 | Circuit arrangement for deriving at least one quality signal which is dependent on the quality of a received signal |
PCT/DE1994/000321 WO1994022229A1 (en) | 1993-03-24 | 1994-03-22 | Circuit for deriving audio signal masking signals |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0691050A1 true EP0691050A1 (en) | 1996-01-10 |
EP0691050B1 EP0691050B1 (en) | 1996-12-18 |
Family
ID=38729052
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94911062A Expired - Lifetime EP0691050B1 (en) | 1993-03-24 | 1994-03-22 | Circuit for deriving audio signal masking signals |
Country Status (5)
Country | Link |
---|---|
US (1) | US5661810A (en) |
EP (1) | EP0691050B1 (en) |
JP (1) | JP3676363B2 (en) |
DE (1) | DE59401348D1 (en) |
WO (1) | WO1994022229A1 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4434451A1 (en) * | 1994-09-27 | 1996-03-28 | Blaupunkt Werke Gmbh | Amplitude demodulator |
EP0776144B1 (en) * | 1995-11-25 | 2001-04-11 | Micronas GmbH | Signal modification circuit |
DE19630395C1 (en) * | 1996-07-26 | 1997-10-02 | Sgs Thomson Microelectronics | Electrical mute control circuit for audio signal |
US6856925B2 (en) * | 2001-10-26 | 2005-02-15 | Texas Instruments Incorporated | Active removal of aliasing frequencies in a decimating structure by changing a decimation ratio in time and space |
DE10224699A1 (en) * | 2002-06-04 | 2003-12-24 | Bosch Gmbh Robert | Method and circuit arrangement for influencing the height reproduction of an audio signal |
DE102010001548A1 (en) | 2009-11-18 | 2011-05-19 | Robert Bosch Gmbh | Circuit arrangement for a receiver |
KR20130115286A (en) * | 2010-11-05 | 2013-10-21 | 세미컨덕터 아이디어스 투 더 마켓트(아이톰) 비.브이. | Method for reducing noise included in a stereo signal, stereo signal processing device and fm receiver using the method |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5757051A (en) * | 1980-09-22 | 1982-04-06 | Nippon Gakki Seizo Kk | Fm stereo receiver |
US4497063A (en) * | 1981-06-26 | 1985-01-29 | Pioneer Electronic Corporation | FM stereo demodulator |
JPS61263327A (en) * | 1985-05-17 | 1986-11-21 | Pioneer Electronic Corp | Sound multiplex receiver |
MX161741A (en) * | 1987-08-28 | 1990-12-20 | Motorola Inc | IMPROVED MODULATED FREQUENCY COMMUNICATION SYSTEM |
US4901350A (en) * | 1989-04-20 | 1990-02-13 | Delco Electronics Corporation | Closed-loop audio attenuator |
CA2025012A1 (en) * | 1989-09-11 | 1991-03-12 | William R. Short | Audible noise reducing |
US5027402A (en) * | 1989-12-22 | 1991-06-25 | Allegro Microsystems, Inc. | Blend-on-noise stereo decoder |
US5201062A (en) * | 1990-03-28 | 1993-04-06 | Pioneer Electronic Corporation | Noise reducing circuit |
US5257312A (en) * | 1991-05-03 | 1993-10-26 | U.S. Philips Corporation | Time-discrete stereo decoder |
US5249233A (en) * | 1992-04-06 | 1993-09-28 | Ford Motor Company | Multipath noise minimizer for radio receiver |
US5432854A (en) * | 1993-02-25 | 1995-07-11 | Chrysler Corporation | Stereo FM receiver, noise control circuit therefor |
DE4311933A1 (en) * | 1993-04-10 | 1994-10-13 | Blaupunkt Werke Gmbh | Circuit arrangement for generating a stop signal for a station search |
-
1994
- 1994-03-22 DE DE59401348T patent/DE59401348D1/en not_active Expired - Lifetime
- 1994-03-22 WO PCT/DE1994/000321 patent/WO1994022229A1/en active IP Right Grant
- 1994-03-22 EP EP94911062A patent/EP0691050B1/en not_active Expired - Lifetime
- 1994-03-22 US US08/522,314 patent/US5661810A/en not_active Expired - Lifetime
- 1994-03-22 JP JP52052794A patent/JP3676363B2/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO9422229A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE59401348D1 (en) | 1997-01-30 |
US5661810A (en) | 1997-08-26 |
JP3676363B2 (en) | 2005-07-27 |
WO1994022229A1 (en) | 1994-09-29 |
EP0691050B1 (en) | 1996-12-18 |
JPH08508143A (en) | 1996-08-27 |
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