Abstract: Provided is an audio output device capable of preventing noises and improving the S/N ratio even if no audio signal is inputted in the middle of the input of audio signals, or even if an audio-signal input state and a no-signal state are alternately repeated. In the provided audio output device, a multiplier is provided on the input side of each of the delayers. Each multiplier multiplies the addition output of the corresponding one of adders by a multiplier coefficient supplied by the coefficient counter. If there is no input of digital audio signals into a ?? modulator, the counter control circuit decreases the output of the coefficient counter down to 0 stepwise at predetermined intervals.

Abstract: A sine wave generating device includes at least one adder configured to add two input signals thereof, at least one delay unit configured to delay an input signal thereof by one sample time and at least one multiplier configured to receive the delayed signal from the at least one delay unit, multiply the delayed signal by a coefficient and output the multiplied signal to provide to the at least one adder. The coefficient is arbitrarily set from outside the sine wave generating device.

Abstract: An absolute-value circuit outputs the absolute value of a signal SIN? that corresponds to an input signal SIN. A clipping circuit clips the signal SIN? that corresponds to the input signal, to a positive limit value and to a negative limit value. A first multiplier multiplies the signal SIN? that corresponds to the input signal, by a predetermined coefficient. A first adder subtracts the output signal of the first multiplier from the output signal of the clipping circuit. A second adder sums a signal that corresponds to the output signal of the first adder and a signal that corresponds to the output signal of the absolute-value circuit. A third adder sums the input signal SIN and a signal that corresponds to the output signal of the second adder.

Abstract: Provided is an audio output device capable of preventing noises and improving the S/N ratio even if no audio signal is inputted in the middle of the input of audio signals, or even if an audio-signal input state and a no-signal state are alternately repeated. In the provided audio output device, a multiplier is provided on the input side of each of the delayers. Each multiplier multiplies the addition output of the corresponding one of adders by a multiplier coefficient supplied by the coefficient counter. If there is no input of digital audio signals into a ?? modulator, the counter control circuit decreases the output of the coefficient counter down to 0 stepwise at predetermined intervals.

Abstract: Provided is an audio output device capable of preventing noises and improving the S/N ratio even if no audio signal is inputted in the middle of the input of audio signals, or even if an audio-signal input state and a no-signal state are alternately repeated. In the provided audio output device, a multiplier is provided on the input side of each of the delayers. Each multiplier multiplies the addition output of the corresponding one of adders by a multiplier coefficient supplied by the coefficient counter. If there is no input of digital audio signals into a ?? modulator, the counter control circuit decreases the output of the coefficient counter down to 0 stepwise at predetermined intervals.

Abstract: A pseudo bass generating apparatus includes a first 4th-order LPF, an absolute value circuit, a clip circuit, a multiplier, a first adder for subtracting an output signal of the multiplier from an output signal of the clip circuit, a second adder for adding an output signal of the first adder and an output signal of the absolute value circuit, a second 4th-order LPF, and a third adder for adding the input signal and an output signal of the second 4th-order LPF.

Abstract: A variable gain amplifier amplifies an input audio signal. A first control unit monitors the level of the input audio signal, and sets the gain of the variable gain amplifier to a predetermined fixed value when this level is lower than a predetermined minimum threshold. A second control unit monitors the level of an output signal VO of the variable gain amplifier. When this level exceeds a predetermined maximum threshold, the second control unit lowers the gain of the variable gain amplifier. When this level becomes smaller than this threshold, it raises the gain. When the level of the input audio signal is smaller than the minimum threshold, the first control unit disables the gain control operation of the variable gain amplifier controlled by the second control unit. A sub-amplifier amplifies the input audio signal. An output mixing unit mixes signals output from the variable gain amplifier and the sub-amplifier.

Abstract: A sine wave generating device includes at least one adder configured to add two input signals thereof, at least one delay unit configured to delay an input signal thereof by one sample time and at least one multiplier configured to receive the delayed signal from the at least one delay unit, multiply the delayed signal by a coefficient and output the multiplied signal to provide to the at least one adder. The coefficient is arbitrarily set from outside the sine wave generating device.

Abstract: A pseudo bass generating apparatus includes a first 4th-order LPF, an absolute value circuit, a clip circuit, a multiplier, a first adder for subtracting an output signal of the multiplier from an output signal of the clip circuit, a second adder for adding an output signal of the first adder and an output signal of the absolute value circuit, a second 4th-order LPF, and a third adder for adding the input signal and an output signal of the second 4th-order LPF.

Abstract: Provided is an audio output device capable of preventing noises and improving the S/N ratio even if no audio signal is inputted in the middle of the input of audio signals, or even if an audio-signal input state and a no-signal state are alternately repeated. In the provided audio output device, a multiplier is provided on the input side of each of the delayers. Each multiplier multiplies the addition output of the corresponding one of adders by a multiplier coefficient supplied by the coefficient counter. If there is no input of digital audio signals into a ?? modulator, the counter control circuit decreases the output of the coefficient counter down to 0 stepwise at predetermined intervals.

Abstract: An absolute-value circuit outputs the absolute value of a signal SIN? that corresponds to an input signal SIN. A clipping circuit clips the signal SIN? that corresponds to the input signal, to a positive limit value and to a negative limit value. A first multiplier multiplies the signal SIN? that corresponds to the input signal, by a predetermined coefficient. A first adder subtracts the output signal of the first multiplier from the output signal of the clipping circuit. A second adder sums a signal that corresponds to the output signal of the first adder and a signal that corresponds to the output signal of the absolute-value circuit. A third adder sums the input signal SIN and a signal that corresponds to the output signal of the second adder.

Abstract: A variable gain amplifier amplifies an input audio signal. A first control unit monitors the level of the input audio signal, and sets the gain of the variable gain amplifier to a predetermined fixed value when this level is lower than a predetermined minimum threshold. A second control unit monitors the level of an output signal VO of the variable gain amplifier. When this level exceeds a predetermined maximum threshold, the second control unit lowers the gain of the variable gain amplifier. When this level becomes smaller than this threshold, it raises the gain. When the level of the input audio signal is smaller than the minimum threshold, the first control unit disables the gain control operation of the variable gain amplifier controlled by the second control unit. A sub-amplifier amplifies the input audio signal. An output mixing unit mixes signals output from the variable gain amplifier and the sub-amplifier.