摘要
通过对比验证几种常用的中低频频率特性测试方法,提出了一种基于零中频正交解调原理的中低频频率特性测试仪的设计方法。将被测网络的输出信号分别与两路正交输入信号相乘,并用低通滤波器将其交流成分滤除,其结果中的直流分量便包含了被测网络的幅频特性和相频特性信息。整个系统仅采用模拟乘法器对信号进行混频,无源低通滤波器对信号进行解调,简化了电路结构。采用高精度AD进行模数转换,提高了测试精度。
Problems of complex structure of frequency characteristics tester circuit and low accuracy of lower frequency measurement are investigated by verification of several commonly used in low-frequency characteristics of the test methods. A new method for low frequency characteristics tester is proposed based on the principle of zero-if quadrature demodulation. The output signal of the network is sent to two quadrature and multiplied. A low-pass filter is used to filter out the AC component,and the result will be the DC component only which contains amplitude-frequency characteristic and phase-frequency characteristic information of test network. The entire system uses only the analog signal multiplier for mixing,passive low-pass filter for demodulating the signal,hence,the circuit configuration is simplified. A high-precision analog-digital conversion is used to transfer AD signal,it improves test accuracy.
出处
《实验室研究与探索》
CAS
北大核心
2016年第6期62-65,共4页
Research and Exploration In Laboratory
关键词
零中频正交解调
频率特性
直流分量
交流分量
模拟乘法器
zero-if quadrature demodulation
frequency characteristic
DC value
AC value
analog multiplier
