Audio output device
AssigneeRohm Co., Ltd.
InventorYasutomo YOKOYAMA
Life of this patent
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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 ΔΣ modulator, the counter control circuit decreases the output of the coefficient counter down to 0 stepwise at predetermined intervals.
Claims9
An audio output device comprising a ΔΣ modulator including:
- a quantizer configured to quantize a signal;
- a subtractor configured to subtract a feedback signal from the quantizer from an inputted digital audio signal;
- an accumulator configured to accumulate output signals from the subtractor and to output the accumulated output signals to the quantizer side;
- a delayer included in the accumulator;
- and
- a multiplier included in the accumulator and connected to an input side of the delayer, wherein
- in the ΔΣ modulator, an output of the multiplier is set to 0 if there is no input of the digital audio signal during a predetermined period.
Dependencies are inferred from the claim text.