Design of a High-Performance Programmable Filter Based on TLC7528

Abstract

High-performance filter is the key to improving the detection accuracy of geophysical instruments. In order to achieve high-precision measurement of small signals, this paper presents a design of high-performance programmable filter based on TLC7528. The system design mainly included programmable amplifier circuit design, programmable filter circuit design, amplitude-frequency test circuit design, display circuit and the keyboard circuit design. The system used a microcontroller as the control center for system parameters setting and control, adopted analog switches and selected low-noise op amp to achieve programmable gain control, used TLC7528 to realize the filter cut off frequency adjustable by changing its internal resistance value and used the DDS chip and RMS conversion chip to design the circuit of amplitude-frequency characteristics, so as to test and analysis the signal amplitude and frequency of the system design filter. The experimental test data showed that the high performance filter has the characteristics of good linear, small voltage gain error, low power, flexibility and little environmental impact. It can significantly improve the accuracy of the geophysical detection equipment.