| 摘要 |
PURPOSE:To improve accuracy for digital data by separating the sampling noise and quantizing error noise of an analog input signal from the analog input signal. CONSTITUTION:The analog input signal is sampled (101) and converted to a digital signal (102), the digital signal and a digital signal (105) having a value different from that of the digital signal are laternately sampled, a digital filter processing is executed, and a high frequency component is removed (103). Otherwise, a signal superimposing an AC signal at a fixed frequency to the analog input signal is sampled and converted to a digital signal (102), the digital filter processing is executed to that digital signal, and the high frequency component is removed (103). Otherwise, DELTASIGMA modulation is executed to the analog input signal, the digital filter processing is executed to the modulated signal, and the high frequency component is removed. Thus, the frequency areas of disturbance noise and noise caused by quantizing error can be moved to a high frequency area in the block area of a digital filter, and resolution higher than that of an A/D converter can be effectively utilized. |
