| 摘要 |
PURPOSE: A method of removing click/pop noise in a digital audio system is provided to eliminate the cause of generating the click/pop noise using digital attenuation without using separate hardware. CONSTITUTION: A sigma-delta digital-analog converter includes an input interface converter, a microcomputer interface that generates a control signal for carrying out multiple functions, a finite impulse response filter that executes over-sampling, a sigma-delta modulator that carries out noise shaping, an analog post filter for removing quantization noise, and an anti-imaging filter for removing a sampling image. A method of removing noise in the sigma-delta digital-analog converter includes a step of waiting for an input signal(S10), a step of applying digital attenuation when muting, resetting and power down functions are performed for the input signal(S31,S32), and a step of outputting a signal computed according to the digital attenuation to the sigma-delta modulator(40).
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