wseas-12065-20260921064519-4a93c5 20260921064519738 wseas/wseas wseas.group@gmail.com WSEAS WSEAS Transactions on Communications 1109-2742 2224-2864 04 03 2026 04 03 2026 25 Karl Heinz Kraft Faculty of Electrical Engineering, Ostfalia University of Applied Sciences, Salzdahlumer Str. 46-48 D-38302 Wolfenbüttel, GERMANY Safety and efficiency of modern transportation systems require the intensive use of data transmission devices. They should operate in both directions between on-board and wayside equipment. Especially, high-speed applications require a suitable data transmission rate. The design of the entire transmission path has to consider the input and output signals of all the involved components, investigated here for the modulation method FSK. It is demonstrated how the transient behaviour can be simulated using SPICE subcircuits. The main components to be modelled are the following: modulator, a fixed and a movable inductive loop, connected to an input and an output filter, amplifier and limiter, and demodulator. 09 21 2026 09 21 2026 25 4 https://creativecommons.org/licenses/by/4.0/ 10.37394/23204.2026.25.4 https://wseas.com/journals/articles.php?id=12065 D. M. Dobkin; The RF in RFID. Elsevier, Oxford (UK), 2013, ISBN: 9780123945839, https://shop.elsevier.com/books/the-rf-in-rfid/dobkin/978-0-12-394583-9 [Access Date: 01/01/2026]. T. Igoe, D. Coleman, B. Jepson: Beginning NFC. O’Reilly Media, 2014, ISBN: 9781449372064, https://www.oreilly.com/library/view/beginning-nfc/9781449324094 [Access Date: 01/01/2026]. R. A. Gheorghiu, I. Badescu, R. S. Timnea: Infrastructure to vehicle communications using inductive loops. WSEAS Trans. on Communications, Vol. 13 (2014), pp. 596-605, https://www.wseas.org/multimedia/journals/communications/2014/a205704-095.pdf[Access Date: 01/01/2026]. M.Vajdik, D., I. Herman, M. Habr: Data Transmission Using Inductive Method In Mobile Applications. https://www.wseas.us/e-library/conferences/2005athens/cscc/papers/497-319.pdf [Access Date: 01/01/2026]. Eurika, FSK Explained: Principles, Applications, and Benefits. https://eureka.patsnap.com/blog/what-is-fsk/[Access Date: 01/01/2026]. RFEngineer- Frequency Shift Keying (FSK): Theory and Applications https://rfengineer.net/basic-concepts/frequency-shift-keying-fsk-theory-and-applications/[Access Date: 01/01/2026]. (text in German). Kaden, Heinrich: Impulse und Schaltvorgänge in der Nachrichtentechnik . R. Oldenbourg, Munich 1957, https://www.booklooker.de/B%C3%BCcher/Heinrich-Kaden+Impulse-und-Schaltvorg%C3%A4nge-in-der-Nachrichtentechnik/id/A02KiD6Z01ZZ3[Access Date: 01/01/2026]. Kraft, K. H.: Broadband-matching of coupled inductive loops used for vehicle communications. WSEAS Trans. on Communications, 2025, vol. 24, pp. 11-16. doi: 10.37394/23204.2025.24.3, https://wseas.com/journals/articles.php?id=10656 [Access Date: 01/01/2026]. (text in German) Küpfmüller, K.: Die Systemtheorie der elektrischen Nachrichten-übertragung. S. Hirzel Verlag, Stuttgart 1952. Resources.pcb.cadence.com c› pspiceuserguide › 06-analog-behavioral-modeling [Access Date: 01/01/2026]. Rhode & Schwarz, R&S SMW200A user manual. https://www.rohde-schwarz.com/us/manual/rs-smw200a-user-manual_78701-61762.html; [Access Date: 01/01/2026].