Abstract: The present invention relates to computing circuits and method for running an MPEG-2 AAC or MPEG-4 AAC algorithm efficiently, which is used as an audio compression algorithm in multi-channel high-quality audio systems, on programmable processors. In accordance with the present invention, the IMDCT process which takes large part of the amount of the operations in implementation of an MPEG-2/4 AAC algorithm can be performed in efficient. In addition, while the architecture of the existing digital signal processor is still used, the performance can be improved by means of the addition of the architecture of the address generator, Huffman decoder, and bit processing architecture. After all, to design and change the programmable processor is facilitated.

Abstract: The present invention relates to computing circuits and method for running an MPEG-2 AAC or MPEG-4 AAC algorithm efficiently, which is used as an audio compression algorithm in multi-channel high-quality audio systems, on programmable processors. In accordance with the present invention, the IMDCT process which takes large part of the amount of the operations in implementation of an MPEG-2/4 AAC algorithm can be performed in efficient. In addition, while the architecture of the existing digital signal processor is still used, the performance can be improved by means of the addition of the architecture of the address generator, Huffman decoder, and bit processing architecture. After all, to design and change the programmable processor is facilitated.

Abstract: The present invention relates to computing circuits and method for running an MPEG-2 AAC or MPEG-4 AAC algorithm efficiently, which is used as an audio compression algorithm in multi-channel high-quality audio systems, on programmable processors. In accordance with the present invention, the IMDCT process which takes large part of the amount of the operations in implementation of an MPEG-2/4 AAC algorithm can be performed in efficient. In addition, while the architecture of the existing digital signal processor is still used, the performance can be improved by means of the addition of the architecture of the address generator, Huffman decoder, and bit processing architecture. After all, to design and change the programmable processor is facilitated.

Abstract: A pulse width modulator for use in a digital amplifier, includes a pop noise reducer for reducing pop noise by controlling a width and a phase of a pulse of a PWM signal output from the pulse width modulator, wherein the pop noise reducer contains: a PWM pulse register for storing a width and a phase values of a pulse of the PWM signal; and a pulse generator for outputting the PWM signal according to the values stored in the PWM pulse register. The pulse width modulator reduces pop noise generated when power supply to a digital amplifier is started and interrupted.

Abstract: The present invention relates to the computing method and Huffman computing circuits for improving the correctness and efficiency of the nonlinear inverse quantization when the MPEG-2 AAC (Advanced Audio Coding) or MPEG-4 AAC algorithm which is used as an audio compression algorithm in multi-channel high-quality audio systems is implemented on programmable processors. In accordance with the present invention, while the architecture of the existing digital signal processor is reused, the performance can be improved by means of the addition of Huffman decoder and bit processing architecture. Accordingly, to design and change the programmable processor can be facilitated.

Abstract: A method and an apparatus for outputting an audio signal are provided. The apparatus includes a power source; a compensator for compensating an input signal by adding the input signal to an offset value reciprocally proportional to a source voltage; a pulse width modulator for modulating an audio signal transmitted from the compensator; and an output stage for outputting the modulated audio signal. Accordingly, audio quality can be improved directly for a listener by compensating the input signal damaged by periodical voltage drops.

Abstract: A method and an apparatus for outputting an audio signal are provided. The apparatus includes a power source; a compensator for compensating an input signal by adding the input signal to an offset value reciprocally proportional to a source voltage; a pulse width modulator for modulating an audio signal transmitted from the compensator; and an output stage for outputting the modulated audio signal. Accordingly, audio quality can be improved directly for a listener by compensating the input signal damaged by periodical voltage drops.

Abstract: The present invention relates to the computing method and Huffman computing circuits for improving the correctness and efficiency of the nonlinear inverse quantization when the MPEG-2 AAC (Advanced Audio Coding) or MPEG-4 AAC algorithm which is used as an audio compression algorithm in multi-channel high-quality audio systems is implemented on programmable processors. In accordance with the present invention, while the architecture of the existing digital signal processor is reused, the performance can be improved by means of the addition of Huffman decoder and bit processing architecture. Accordingly, to design and change the programmable processor can be facilitated.

Abstract: The present invention relates to computing circuits and method for running an MPEG-2 AAC or MPEG-4 AAC algorithm efficiently, which is used as an audio compression algorithm in multi-channel high-quality audio systems, on programmable processors. In accordance with the present invention, the IMDCT process which takes large part of the amount of the operations in implementation of an MPEG-2/4 AAC algorithm can be performed in efficient. In addition, while the architecture of the existing digital signal processor is still used, the performance can be improved by means of the addition of the architecture of the address generator, Huffman decoder, and bit processing architecture. After all, to design and change the programmable processor is facilitated.

Abstract: A pulse width modulator for use in a digital amplifier, includes a pop noise reducer for reducing pop noise by controlling a width and a phase of a pulse of a PWM signal output from the pulse width modulator, wherein the pop noise reducer contains: a PWM pulse register for storing a width and a phase values of a pulse of the PWM signal; and a pulse generator for outputting the PWM signal according to the values stored in the PWM pulse register. The pulse width modulator reduces pop noise generated when power supply to a digital amplifier is started and interrupted.

Abstract: The present invention relates to an audio amplifier using a pulse width modulation, and more particularly, to a pulse width modulation type audio amplifier which an average switching frequency or a cutoff frequency of a low pass filter is variable in accordance with frequency of input signal.

Abstract: Disclosed is a demodulation apparatus for a digital audio amplifier capable of solving a space, cost and heat generation of the digital audio amplifier. The demodulation apparatus includes a first inductor connected between a positive digital audio signal output terminal and one end of a load, a second inductor connected between a negative digital audio signal output terminal and the other end of the load, and magnetically coupled to the first inductor, a first capacitor connected between the one end of the load and ground and coupled to the first inductor for serving as a low-pass filter, and a second capacitor connected between the other end of the load and ground and connected to the second inductor for serving as a low-pass filter.

Abstract: Disclosed is a demodulation apparatus for a digital audio amplifier capable of solving a space, cost and heat generation of the digital audio amplifier. The demodulation apparatus includes a first inductor connected between a positive digital audio signal output terminal and one end of a load, a second inductor connected between a negative digital audio signal output terminal and the other end of the load, and magnetically coupled to the first inductor, a first capacitor connected between the one end of the load and ground and coupled to the first inductor for serving as a low-pass filter, and a second capacitor connected between the other end of the load and ground and connected to the second inductor for serving as a low-pass filter.

Abstract: The present invention relates to an audio amplifier using a pulse width modulation, and more particularly, to a pulse width modulation type audio amplifier which an average switching frequency or a cutoff frequency of a low pass filter is variable in accordance with frequency of input signal.