摘要
以OTA(运算跨导放大器)通用滤波器增益的计算为例,将拆环法推广到多环系统。拆环时可拆开任意一个环,其余部分视为一个无反馈系统,先求环路增益,再求前向通路增益,即可用反馈电路的基本方程求出闭环增益。强调拆分不同的反馈环,将有不同的环路增益和前向通路增益,但闭环增益不变。分析还表明,若能使拆分点把所有环路均断开,则可使环路增益、前向通路增益计算简便,从而使增益的计算更简单、实用。因此,推广的拆环法可快速计算高阶滤波器增益,适宜推广。
Taking calculation of the gain of universal two order filter on OTA＇s as example, an open-loop method was extended to the system with multiple feedback paths. It is pointed out that when a loop path is cut off, the rest of the circuit is regarded as to have no feedback, and the loop gain and forward channel gain can be calculated, and the closed loop gain can also be calculated basing on the basic equation of feedback circuit. It is stressed that the loop gain and forward channel gain change with the loop path cut off, but the closed loop gain remains unchanges. If cutting off point cuts all loop paths off, the loop gain and forward channel gain can be calculated simply. Thus we can simplify the method of calculating the closed loop gain. In a word, we can calculate the gain of high order filter in short time by extended open-loop method, which is suitable to popularize.
出处
《电子工程师》
2007年第1期35-37,共3页
Electronic Engineer
基金
咸阳师范学院专项科研基金(05xsky204)
