Audio signal processing apparatus and related computer program
View Patent ↗An audio signal processing apparatus includes first and second tables. The first table has coefficients. The second table has corrective values for correction of the coefficients in the first table. The corrective values are assigned to different sample numbers in at least two successive half-wave signal portions. Detection is made as to a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion. The coefficients in the first table are corrected into correction-resultant coefficients in response to the detected sample numbers while the corrective values in the second table are used. Samples in the corrected-object half-wave portion of the digital audio signal are corrected in response to the correction-resultant coefficients.
1. An audio signal processing apparatus comprising:
a first table having coefficients;
a second table having corrective values for correction of the coefficients in the first table, the corrective values being assigned to different sample numbers in at least two successive half-wave signal portions;
first means for detecting a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion;
second means for selecting ones from the corrective values in the second table in accordance with the sample numbers detected by the first means;
third means for correcting the coefficients in the first table into correction-resultant coefficients in response to the corrective values selected by the second means; and
fourth means for correcting samples in the corrected-object half-wave portion of the digital audio signal in response to the correction-resultant coefficients generated by the third means.
2. A computer readable medium storing a computer program for audio signal processing in which a first table has coefficients, and a second table has corrective values for correction of the coefficients in the first table, the corrective values being assigned to different sample numbers in at least two successive half-wave signal portions, the computer program comprising the steps of:
a) detecting a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion;
b) selecting ones from the corrective values in the second table in accordance with the sample numbers detected by the step a);
c) correcting the coefficients in the first table into correction-resultant coefficients in response to the corrective values selected by the step b); and
d) correcting samples in the corrected-object half-wave portion of the digital audio signal in response to the correction-resultant coefficients generated by the step c).
3. An audio signal processing apparatus comprising:
a first table having coefficients;
a second table having corrective values for correction of the coefficients in the first table, the corrective values being assigned to different sample numbers in at least two successive half-wave signal portions;
first means for detecting a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion;
second means for selecting ones from the corrective values in the second table in accordance with the sample numbers detected by the first means;
third means for correcting the coefficients in the first table into correction-resultant coefficients in response to the corrective values selected by the second means;
fourth means for detecting a difference between a level represented by a sample of interest in the corrected-object half-wave portion of the digital audio signal and a level represented by a sample which immediately precedes the sample of interest;
fifth means for multiplying the difference detected by the fourth means and corresponding one of the correction-resultant coefficients generated by the third means to get a multiplication result; and
sixth means for adding the multiplication result generated by the fifth means to the level represented by the sample of interest to correct the sample of interest.
4. A computer readable medium storing a computer program for audio signal processing in which a first table has coefficients, and a second table has corrective values for correction of the coefficients in the first table, the corrective values being assigned to different sample numbers in at least two successive half-wave signal portions, the computer program comprising the steps of:
a) detecting a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion;
b) selecting ones from the corrective values in the second table in accordance with the sample numbers detected by the step a);
c) correcting the coefficients in the first table into correction-resultant coefficients in response to the corrective values selected by the step b);
d) detecting a difference between a level represented by a sample of interest in the corrected-object half-wave portion of the digital audio signal and a level represented by a sample which immediately precedes the sample of interest;
e) multiplying the difference detected by the step d) and corresponding one of the correction-resultant coefficients generated by the step c) to get a multiplication result; and
f) adding the multiplication result generated by the step e) to the level represented by the sample of interest to correct the sample of interest.