WANG Teng fei1, WANG Teng shuai2, ZHANG Zong yan3

 

(1. Department of Mechanical and Electrical Engineer, Datong Vocational and Technical College of Coal,

 

Datong 037000, China; 2. Graduate School, University of Science & Technology of Heilongjiang,

 

Harbin 150027, China; 3. Shanghai Nanzi Science & Technology Co., Ltd., Shanghai 200333, China)

 

 

Abstract: Aiming at the problem of the characteristics shortcomings of Butterworth and Chebyshev low pass filters, the amplitude frequency characteristic, the filtering effect and the principle of negative feedback were analyzed and researched, a design method of low pass filter based on the principle of negative feedback was investigated, The transfer function of the design circuit was theoretically deduced, the transfer function was compared with that of low pass filter, the relations between the circuit parameters and component values was established, and the method of software simulation to confirm the approximate range of the parameters was presented, so as to meet the requirement of the design, the parameters was adjusted constantly. The results indicate that the cut off characteristics and frequency of low pass filter circuit based on negative feedback is better, the fading characteristic is steeper, and the frequency band is smoother, which can meet the actual needs.

 

Key words: low pass filter; negative feedback; amplitude frequency characteristics; function approximation