Implementation of Filter Structures in VLF Band for Remote Sensing Systems Using MCFOA

Abstract

This paper presents analogue current-mode filter circuits for the very low frequency (VLF) band (3–30 kHz), intended for remote sensing applications. The proposed designs include first-order low-pass, high-pass, and all-pass filters, together with a single-input, three-output universal filter providing simultaneous low-pass, high-pass, and all-pass responses. Each structure employs a single modified current feedback operational amplifier (MCFOA) and only four grounded passive components, enabling a simple and compact implementation. Designed at a cut-off frequency of 10 kHz, the filters achieve a total harmonic distortion (THD) of ≤1.5%, a dynamic range (DR) greater than 60 dB, and power consumption below 1 mW with a 2.5 V single supply. Frequency and gain can be adjusted through passive component selection. Moreover, the use of a 100 pF capacitance supports VLSI and low-voltage/low-power implementations. The proposed circuits are verified through PSpice simulations.

Keywords

• Very low frequency (VLF)
• Modified Current Feedback Operational Amplifier (MCFOA)
• Current-mode filters

Ethical Statement

This study does not involve any human or animal subjects and therefore does not require an ethical approval.

References

1. [1]. Demir, U, Saraçoğlu, M S, Toker, C. Geniş Bant Yer Tabanlı bir VLF/LF Alıcı Sisteminin Analog Ön-uç Tasarımı.
2. [2]. Toker, A, Kuntman, H, Cicekoglu, O, Discigil, M. 2002. New oscillator topologies using inverting second-generation current conveyors. Turkish Journal of Electrical Engineering & Computer Sciences; 10: 119–130.
3. [3]. Smith, K C, Sedra, A. 1968. The current conveyor—A new circuit building block. Proceedings of the IEEE; 56: 1368–1369.
4. [4]. Sedra, A, Smith, K. 1970. A second-generation current conveyor and its applications. IEEE Transactions on Circuit Theory; 17: 132–134.
5. [5]. Fabre, A. 1995. Third-generation current conveyor: a new helpful active element. Electronics Letters; 31: 338–339.
6. [6]. Fabre, A, Saaid, O, Wiest, F, Boucheron, C. 1996. High frequency applications based on a new current controlled conveyor. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications; 43: 82–91.
7. [7]. Yuce, E, Minaei, S. 2009. ICCII-based universal current-mode analog filter employing only grounded passive components. Analog Integrated Circuits and Signal Processing; 58: 161–169.
8. [8]. Soltan, A, Radwan, A G, Soliman, A M. 2014. CCII based fractional filters of different orders. Journal of Advanced Research; 5: 157–164.

9. [9]. Yucel, F, Yuce, E. 2014. CCII based more tunable voltage-mode all-pass filters and their quadrature oscillator applications. AEU – International Journal of Electronics and Communications; 68: 1–9.
10. [10]. Yuce, E, Kircay, A, Tokat, S. 2008. Universal resistorless current-mode filters employing CCCIIs. International Journal of Circuit Theory and Applications; 36: 739–755.
11. [11]. Sen, F, Kircay, A. 2021. MO-CCCII based current-mode fractional-order universal filter. Journal of Circuits, Systems and Computers; 30: 2150132.
12. [12]. Svoboda, J A, McGory, L, Webb, S. 1991. Applications of a commercially available current conveyor. International Journal of Electronics Theoretical and Experimental; 70: 159–164.
13. [13]. Yuce, E, Verma, R, Pandey, N, Minaei, S. 2019. New CFOA-based first-order all-pass filters and their applications. AEU – International Journal of Electronics and Communications; 103: 57–63.
14. [14]. Senani, R, Bhaskar, D R, Kumar, P. 2021. Two-CFOA-grounded-capacitor first-order all-pass filter configurations with ideally infinite input impedance. AEU – International Journal of Electronics and Communications; 137: 153742.
15. [15]. Raj, A, Bhaskar, D R, Senani, R, Kumar, P. 2022. Extension of recently proposed two-CFOA-GC all-pass filters to the realisation of first-order universal active filters. AEU – International Journal of Electronics and Communications; 154: 119.
16. [16]. Yuce, E, Minaei, S. 2008. A modified CFOA and its applications to simulated inductors, capacitance multipliers, and analog filters. IEEE Transactions on Circuits and Systems I: Regular Papers; 55: 266–275.
17. [17]. Cui, X. 2018. A study of voltage-mode and current-mode filters using modified current feedback operational amplifier. Master’s Thesis, Concordia University.
18. [18]. Herencsar, N, Koton, J, Vrba, K. 2009. Voltage-mode universal filters employing single modified current feedback operational amplifier (MCFOA). In: Proceedings of the International Conference on Electrical and Electronics Engineering (ELECO 2009); II: 83.
19. [19]. Herencsar, N, Koton, J, Lahiri, A, Metin, B, Vrba, K. 2012. A voltage gain-controlled modified CFOA and its application in electronically tunable four-mode all-pass filter design. International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems; 1: 20–25.
20. [20]. Herencsar, N, Koton, J, Vrba, K, Lahiri, A, Metin, B. 2012. Novel dual-mode electronically tunable all-pass filter using voltage gain-controlled MCFOA. In: Proceedings of the 13th International Conference on Optimization of Electrical and Electronic Equipment (OPTIM); 1199–1202.
21. [21]. Kircay, A. 2014. Electronically tunable current-mode square-root-domain first-order multifunction filter. International Journal of Electronics; 101: 212–219.
22. [22]. Bhaskar, D R, Raj, A, Senani, R, Kumar, P. 2022. CFOA-based simple mixed-mode first-order universal filter configurations. International Journal of Circuit Theory and Applications.
23. [23]. Sen, F, Kircay, A, Cobb, B S, Karci, H. 2023. Current-mode fractional-order shelving filters using MCFOA for acoustic applications. AEU – International Journal of Electronics and Communications; 163: 154608.