System for reducing noise sounding in passenger compartment of vehicle
First Claim
Patent Images
1. A system for reducing a sound in a limited space, comprising:
- a) first means for receiving a sound wave generated due to a propagation from a noise source into the limited space, said noise source comprising a vehicular engine, and for transducing the sound wave to output an electrical signal according to the sound wave;
b) second means responsive to the electrical signal from said first means for calculating a new sound wave having the same amplitude as the sound wave and having a phase 180°
opposite to the sound wave on a basis of a spatial acoustic transfer characteristic of the limited space for propagation of the new sound wave, said new sound wave being interfered with the sound wave propagated from the noise source;
c) third means for measuring the spatial acoustic transfer characteristic of the limited space;
d) a volatile memory for storing the measured value of the spatial acoustic transfer characteristic as its stored data;
e) a non-volatile memory for storing a standard value of the spatial acoustic transfer characteristic as its stored data, said second means calculating the new sound wave on the basis of the standard value of the spatial acoustic transfer characteristic derived from the non-volatile memory in place of the measured value of the spatial acoustic transfer characteristic from the volatile memory when the stored data in the volatile memory is erased, andan identifying switch,wherein said second means includes a microprocessor,wherein said microprocessor determines whether the engine is stopped and determines whether the identifying switch is turned on or off upon determining that the engine has stopped, and,when determining that the identifying switch is turned on, said microprocessor compares an identification end code in the volatile memory with an identification end code in the non-volatile memory, determines that the measured value of the spatial acoustic transfer characteristic stored in the volatile memory is a correct value of a newest acoustic transfer characteristic derived upon a previous identification processing when the identification end codes coincide with each other, sets a key code indicating that the data in the volatile memory is correct, and executes the identification processing when the identification end codes do not coincide with each other until the identification end codes coincide with each other.
1 Assignment
0 Petitions
Accused Products
Abstract
A system for reducing a closed sound generated by propagation of vibrations into a limited space such as a vehicular compartment using at least one microphone and at least one speaker. In the closed sound reducing system, a volatile memory such as a RAM is installed for storing a measured newest value of a vibration propagation transfer function cfm(j) and a non-volatile memory such as a ROM is installed for storing a standard value of the vibration propagation transfer function. When the stored data of the volatile memory is erased, the standard value stored in the non-volatile memory is used in place of the measured newest value stored in the volatile memory.
49 Citations
18 Claims
-
1. A system for reducing a sound in a limited space, comprising:
-
a) first means for receiving a sound wave generated due to a propagation from a noise source into the limited space, said noise source comprising a vehicular engine, and for transducing the sound wave to output an electrical signal according to the sound wave; b) second means responsive to the electrical signal from said first means for calculating a new sound wave having the same amplitude as the sound wave and having a phase 180°
opposite to the sound wave on a basis of a spatial acoustic transfer characteristic of the limited space for propagation of the new sound wave, said new sound wave being interfered with the sound wave propagated from the noise source;c) third means for measuring the spatial acoustic transfer characteristic of the limited space; d) a volatile memory for storing the measured value of the spatial acoustic transfer characteristic as its stored data; e) a non-volatile memory for storing a standard value of the spatial acoustic transfer characteristic as its stored data, said second means calculating the new sound wave on the basis of the standard value of the spatial acoustic transfer characteristic derived from the non-volatile memory in place of the measured value of the spatial acoustic transfer characteristic from the volatile memory when the stored data in the volatile memory is erased, and an identifying switch, wherein said second means includes a microprocessor, wherein said microprocessor determines whether the engine is stopped and determines whether the identifying switch is turned on or off upon determining that the engine has stopped, and, when determining that the identifying switch is turned on, said microprocessor compares an identification end code in the volatile memory with an identification end code in the non-volatile memory, determines that the measured value of the spatial acoustic transfer characteristic stored in the volatile memory is a correct value of a newest acoustic transfer characteristic derived upon a previous identification processing when the identification end codes coincide with each other, sets a key code indicating that the data in the volatile memory is correct, and executes the identification processing when the identification end codes do not coincide with each other until the identification end codes coincide with each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A system for reducing a vibration sound propagated into a vehicular compartment, comprising:
-
a) first means for receiving a harmonic sound signal of a vehicular engine vibration sound and outputting, against the harmonic signal, a cancelling sound having a magnitude substantially equal to a magnitude of the vibration sound and having a phase of 180-degrees relative to a phase of the vibration sound; b) second means for detecting a residual vibration sound created by a combination of the vibration sound and the cancelling sound outputted by the first means; c) third means for adaptively adjusting the cancelling sound from the first means on the basis of the residual vibration sound using a vibration propagation spatial acoustic transfer function from a position of the first means to that of the second means so as to reduce a vibration energy detected by the second means, thereby reducing total vibration propagated into the vehicular compartment; d) a volatile memory for storing a measured newest vibration propagation spatial acoustic transfer function so as to update a previously measured vibration propagation spatial acoustic transfer function; e) a non-volatile memory for storing a predetermined standard value of the vibration propagation spatial acoustic transfer function, and an identifying switch, wherein said third means includes a microprocessor, wherein said microprocessor determines whether the engine is stopped and determines whether the identifying switch is turned on or off upon determining that the engine has stopped, and, when determining that the identifying switch is turned on, said microprocessor compares an identification end code in the volatile memory with an identification end code in the non-volatile memory, determines that the measured value of the spatial acoustic transfer characteristic stored in the volatile memory is a correct value of the newest acoustic transfer characteristic derived upon a previous identification processing when the identification end codes coincide with each other, sets a key code indicating that the data in the volatile memory is correct, and executes the identification processing when the identification end codes do not coincide with each other until the identification end codes coincide with each other, and wherein said microprocessor of said third means adjusts the cancelling sound using the vibration - View Dependent Claims (14, 15)
-
-
16. A system for reducing a sound in a limited space, comprising:
-
a) first means for receiving a sound wave generated due to a propagation from a noise source into the limited space, said noise source comprising a vehicular engine, and for transducing the sound wave to output an electrical signal according to the sound wave; b) second means responsive to the electrical signal from said first means for calculating a new sound wave having the same amplitude as the sound wave and having a phase 180°
opposite to the sound wave on a basis of an acoustic transfer characteristic of the limited space, said new sound wave interfering with said sound wave to reduce the total sound in the limited space;c) third means for measuring the acoustic transfer characteristic of the limited space; d) a volatile memory for storing the measured value of the acoustic transfer characteristic as its stored data; e) a non-volatile memory for storing a standard value of the acoustic transfer characteristic as its stored data, said second means calculating the new sound wave on the basis of the standard value of the acoustic transfer characteristic derived from the non-volatile memory when the stored data in the volatile memory is erased, and f) fourth means, comprising an identifying switch for inputting a signal to said second means, wherein said second means includes a microprocessor, wherein said microprocessor determines whether the engine is stopped and determines whether the identifying switch is turned on or off upon determining that the engine has stopped, and, when determining that the identifying switch is turned on, said microprocessor compares an identification end code in the volatile memory with an identification end code in the non-volatile memory, determines that the measured value of the acoustic transfer characteristic stored in the volatile memory is a correct value of a newest acoustic transfer characteristic derived upon a previous identification processing when the identification end codes coincide with each other, sets a key code indicating that the data in the volatile memory is correct, and executes the identification processing when the identification end codes do not coincide with each other until the identification end codes coincide with each other, said microprocessor being further responsive to said signal from said fourth means by selecting one of said measured acoustic transfer characteristic from said volatile memory and said standard value of the acoustic transfer characteristic from said non-volatile memory for calculating the new sound wave. - View Dependent Claims (17, 18)
-
Specification