The development of a fully balanced active-RC low-pass filter

Abstract

This research presents the comprehensive development and analysis of a fully balanced active-RC low-pass filter, specifically designed to deliver high efficiency, tunability, and precision in signal processing applications. The filter architecture comprises four bipolar junction transistors (BJTs) as active elements, connected to two resistors (RL and Ree) and one capacitor as passive components, ensuring a robust configuration. This balanced design facilitates the generation of high-resolution and stable signals, with circuit performance closely aligning with simulation results obtained using the PSpice program. By methodically adjusting the bias current (If), capacitance (C), and resistance values (RL and Ree), the operating frequency (f0) of the filter can be finely tuned to meet specific application requirements. The results indicate that the transfer function exhibits a response of approximately –37.00 dB, with a phase shift of –45 degrees. Further analysis reveals that the operating frequency (f0) can be effectively increased by reducing the values of the capacitor (C) and the resistors (RL and Ree). Additionally, the total harmonic distortion (THD) of the output waveform was measured at 9.563 % using fast Fourier transform (FFT) analysis, demonstrating the filter’s capacity to maintain signal integrity. Key highlights of the fully balanced active-RC low-pass filter include high efficiency, flexible tuning capabilities, and accurate performance evaluation through simulation. Suggestions for future development focus on optimizing the filter to minimize THD, testing performance under various environmental conditions, exploring circuit integration for specialized applications, and investigating potential uses in digital signal processing system