SPEED DEPENDENT EQUALIZING CONTROL SYSTEM
First Claim
1. A system for automatic determination of at least one of equalization filter parameters or gain parameters used for equalization of audio signals reproduced in a vehicle, the system comprising:
- an audio amplifier configured to reproduce an audible test signal using at least one loudspeaker arranged in a passenger compartment of the vehicle so as to generate a corresponding acoustic test signal;
at least one microphone arranged at an at least one desired listening position and configured to sequentially pick up the audible test signal as a measured test signal at different volume levels, as well as a noise signal at different non-acoustical measurement values representing a current state of the vehicle;
a signal acquisition and processing system configured to receive the measured test signal and the noise signal, as well as the corresponding volume levels and non-acoustical measurement values, the signal acquisition and processing system being configured to;
calculate power spectral density estimations, which depend on the volume levels and, respectively, on the non-acoustical measurement values, of the measured test signal and the noise signal, respectively,calculate corresponding masking thresholds, which depend on the volume levels and, respectively, on the non-acoustical measurement values, from the power spectral density estimations;
calculate, for each pair of volume levels and non-acoustic measurement values, a target equalization curve, the target equalization curve being composed of non-negative values of a difference between a volume-dependent masking threshold calculated from a test signal power spectral density and a masking threshold calculated from a noise signal power spectral density, which depends on the non-acoustic measurement values; and
calculate, for each pair of volume levels and non-acoustic measurement values, filter parameters of a parameterized filter prototype such that a filter magnitude response of the parameterized filter prototype approximates a corresponding target equalization curve.
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Accused Products
Abstract
A speed dependent equalizing control system for automated design of gain and equalization filter parameters can be used for volume and velocity dependent equalization of audio signals reproduced in a vehicle. The system is configured to develop volume-dependent power spectral density estimations based on a test signal received at a number of different volume levels, and develop non-acoustical parameter-dependent power spectral density estimations based on received noise received at a number of different non-acoustical measurement values representing different states of the vehicle. In one example, the non-acoustical measurement values are different velocities, or speeds, of the vehicle. The system may generate filter parameters of a parameterized equalization filter based on a target equalization curve developed by summation of the volume-dependent power spectral density estimates and the non-acoustical measurement-dependent power spectral density estimates.
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Citations
20 Claims
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1. A system for automatic determination of at least one of equalization filter parameters or gain parameters used for equalization of audio signals reproduced in a vehicle, the system comprising:
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an audio amplifier configured to reproduce an audible test signal using at least one loudspeaker arranged in a passenger compartment of the vehicle so as to generate a corresponding acoustic test signal; at least one microphone arranged at an at least one desired listening position and configured to sequentially pick up the audible test signal as a measured test signal at different volume levels, as well as a noise signal at different non-acoustical measurement values representing a current state of the vehicle; a signal acquisition and processing system configured to receive the measured test signal and the noise signal, as well as the corresponding volume levels and non-acoustical measurement values, the signal acquisition and processing system being configured to; calculate power spectral density estimations, which depend on the volume levels and, respectively, on the non-acoustical measurement values, of the measured test signal and the noise signal, respectively, calculate corresponding masking thresholds, which depend on the volume levels and, respectively, on the non-acoustical measurement values, from the power spectral density estimations; calculate, for each pair of volume levels and non-acoustic measurement values, a target equalization curve, the target equalization curve being composed of non-negative values of a difference between a volume-dependent masking threshold calculated from a test signal power spectral density and a masking threshold calculated from a noise signal power spectral density, which depends on the non-acoustic measurement values; and calculate, for each pair of volume levels and non-acoustic measurement values, filter parameters of a parameterized filter prototype such that a filter magnitude response of the parameterized filter prototype approximates a corresponding target equalization curve. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for an automatic design of equalization filter and/or gain parameters used for equalization of audio signals reproduced in a vehicle;
- the method comprising;
reproducing an acoustic test signal using an audio amplifier and at least one loudspeaker arranged in a passenger compartment of the vehicle, the acoustic test signal reproduced at a configurable volume setting; sequentially picking up the acoustic test signal at different volume settings as a measured test signal with at least one microphone arranged at an at least one desired listening position within the vehicle; sequentially picking up a noise signal as a measured noise signal with the at least one microphone at different non-acoustical measurement values representing a current state of the vehicle; calculating power spectral density estimations, which depend on the volume settings and, respectively, on the non-acoustical measurement values, of the measured test signal and the measured noise signal, respectively, calculating corresponding masking thresholds, which depend on the volume settings and, respectively, on the non-acoustical measurement values, from the power spectral density estimations; calculating, for each pair of volume settings and non-acoustical measurement values, a target equalization curve, the target equalization curves being composed of the non-negative values of the difference between a volume-dependent masking threshold, calculated from a test signal power spectral density, and the masking thresholds, calculated from a noise signal power spectral density, which depends on the non-acoustic measurement value; and calculating, for each pair of volume levels and non-acoustic measurement values, filter parameters of a parameterized filter prototype such that a filter magnitude response of the parameterized filter prototype approximates a corresponding target equalization curve. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
- the method comprising;
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16. A system for automated determination of filter parameters used for equalization of audio signals reproduced in a vehicle, the system comprising:
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an audio amplifier configured to drive a loudspeaker to produce audible sound representative of a test signal, a volume level of the audible sound being adjustable; a signal acquisition and processing system configured to receive first measured signals indicative of audible sound sensed by a sensor at each of a plurality of corresponding volume levels, and second measured signals indicative of noise sensed by a sensor for each of a plurality of corresponding non-acoustical measurement values representing a current state of the vehicle; the signal acquisition and processing system further configured to generate volume-dependent power spectral density estimates based on the first measured signals at different volume levels, and non-acoustical measurement-dependent power spectral density estimates based on the second measured signals and the corresponding non-acoustical measurement values; and the signal acquisition and processing system further configured to generate filter parameters of a parameterized equalization filter based on a target equalization curve developed by summation of the volume-dependent power spectral density estimates and the non-acoustical measurement-dependent power spectral density estimates. - View Dependent Claims (17, 18, 19, 20)
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Specification