论文部分内容阅读
一、概述采集与处理低电平信号必须解决低电平外部噪声的抑制问题。任何不能对采集系统提供有用信息的信号均可认为是噪声。根据外部噪声对系统的干扰方式,可将其分成共模噪声与常模噪声两种。常模噪声(Normal mode noise)U_(NM)又称差模(Differential mode)或串模(Series-mode)噪声,它可能是信号源本身产生的,也可能是信号传输线检拾干扰形成的,它与待测信号所处地位相近,串联在测量回路中(图11-1,a)
First, an overview Acquisition and processing of low-level signals must address low-level external noise suppression. Any signal that can not provide useful information to the acquisition system can be considered as noise. According to the external noise on the system interference, it can be divided into two kinds of common mode noise and normal mode noise. Normal mode noise U_ (NM) is also called differential mode or series mode noise. It may be generated by the signal source itself or it may be caused by interference of the signal transmission line. It is similar to the position of the signal under test and is connected in series in the measurement loop (Figure 11-1, a)