International Journal of Electrical and Computer Engineering (IJECE) Vol. 11, No. 4, August 2021, pp. 2962~2973 ISSN: 2088-8708, DOI: 10.11591/ijece.v11i4.pp2962-2973  2962 Journal homepage: http://ijece.iaescore.com One input voltage and three output voltage universal biquad filters with orthogonal tune of frequency and bandwidth May Phu Pwint Wai, Amornchai Chaichana, Winai Jaikla, Surapong Siripongdee, Peerawut Suwanjan Department of Engineering Education, Faculty of Industrial Education and Technology, King Mongkut’s Institute of Technology Ladkrabang, Bangkok Article Info ABSTRACT Article history: Received Nov 30, 2020 Revised Jan 13, 2021 Accepted Jan 29, 2021 This research paper contributes the one input three output voltage mode universal biquad filters with linear and electronic control of the natural frequency (0), using two commercially available ICs, LT1228s as active device with two grounded capacitors, five resistors. The presented universal biquad filters can simultaneously provide three voltage-mode filtering functions, low-pass (LP), high-pass (HP) and band-pass (BP) without changing the circuit architecture. Furthermore, the first presented biquad filter provides low impedance at HP, BP voltage output nodes and LP, BP output voltage nodes are low impedance for the second proposed filter which is easy cascade ability with other voltage mode circuits without the employment of buffer circuits. The quality factor (Q) of both proposed filters is orthogonally adjusted from the passband voltage gain and 0. The proposed filters are simulated and experimented with commercially accessible ICs, LT1228. The simulated and experimental results demonstrate the filtering performances. Keywords: Active building block LT1228 SIMO Universal filter This is an open access article under the CC BY-SA license. Corresponding Author: Amornchai Chaichana Department of Engineering Education, Faculty of Industrial Education and Technology King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520, Thailand Email: amornchai.ch@kmitl.ac.th 1. INTRODUCTION The analog filters or some likeness thereof are basic to the operation of the most engineering circuits. It is hence considering a logical concern for anybody handled with electronic circuit design to be able to create filter circuits fit for meeting a given arrangement of specifications. They are emphasized signals in the specified frequency band (wanted signal) while reject other the signals outside that band (unwanted signal). They are broadly utilized for their significant prerequisites in electrical and electronic engineering application and extremely famous in utilizing for a circuit framework of analog signal processing system. Numerous fields utilize filter circuits, for example, communication, instrumentation, measurement, sound system, and control systems [1]. Particularly, several function filters which are called universal filters or multifunction filters have been extensively studied and have become an interesting research topic. The analog biquad filter with single-input multiple-output (SIMO) category is the most renowned filtering circuit which provides numerous output responses in the same circuit topology. Moreover, SIMO filtering scheme does not want other circuits to get the wanted filtering responses for example the input signal selection. With SIMO feature, the single input is employed and provides simultaneously multiple filtering output responses.