Abstract: 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.

Abstract: A digital audio signal to be replayed is processed in a waveform thereof. A frequency bandwidth of the audio signal is expanded through conversion of a sampling frequency, and then the audio signal is low-pass-filtered with a low-pass cut-off frequency corresponding to the converted sampling frequency. An interval of time between two waveform peaks of the audio signal is detected, and then difference data between current data of the audio signal and past data thereof is calculated. The difference data are subject to weighting depending on the interval, and then output data are produced based on both the low-pass-filtered audio signal and the weighted difference data. This processing, which can be realized by activation of software, improves audio quality when compressed audio data is replayed.

Abstract: 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.

Abstract: A digital audio signal to be replayed is processed in a waveform thereof. A frequency bandwidth of the audio signal is expanded through conversion of a sampling frequency, and then the audio signal is low-pass-filtered with a low-pass cut-off frequency corresponding to the converted sampling frequency. An interval of time between two waveform peaks of the audio signal is detected, and then difference data between current data of the audio signal and past data thereof is calculated. The difference data are subject to weighting depending on the interval, and then output data are produced based on both the low-pass-filtered audio signal and the weighted difference data. This processing, which can be realized by activation of software, improves audio quality when compressed audio data is replayed.