１序言显示仪表在工业生产或试验现场中使用时的条件常常是很复杂的。被测量的参数往往被转换成微弱的低电平电压信号，并经过长距离传输到显示仪表，因此除有用的信号外，由于各种原因，经常会有一些与被测信号无关的电流或电压存在，这种无夫的电流或电压称为“干扰”。热噪 1 The preface shows that the conditions under which the instrument is used in industrial production or in the field of testing are often complex. The measured parameters are often converted to weak low-level voltage signals and transmitted to the display instrument over long distances, so that in addition to the useful signals, there are often a number of currents or voltages that are unrelated to the signal under test for a variety of reasons Existence, this kind of no husband’s current or voltage is called “interference.” Thermal noise