| 摘要 |
PURPOSE: A digital amplifier circuit and a sigma delta modulation method thereof are provided to minimize the additional expense by instead of reducing the pop noise through an analog circuit instead of a digital circuit. CONSTITUTION: A ramp function generating unit(201) generates the ramp function. An input selection unit(202) selects one in response to the selection signal of a PCM signal and ramp function. A delta sigma modulator(203) outputs a delta sigma modulation signal as the delta sigma modulation box selected in the input selection unit. A pulse width modulator(204) outputs the pulse-width modulating signal by modulating the pulse length of the delta sigma modulation signal. A buffer(205) buffers the pulse-width modulating signal. A low-pass filter(206) changes the output of buffer into the analog signal. An output unit(207) outputs the output of the low-pass filter to outside. |
