Z-transform in Telecommunications Systems
review and applications
Introduction: This paper explores the various applications of the Z-Transform in telecommunications, specifically in modulation, demodulation, and Dual-tone Multi-frequency (DTMF) signaling, with a focus on the Goertzel Algorithm.
Problem: There is a gap in understanding the specific applications of the Z-Transform in telecommunications engineering, especially in practical systems like DTMF detection.
Objective: The objective of this study is to analyze recent research on the application of the Z-Transform in telecommunications, with a particular focus on implementing Goertzel’s Algorithm in DTMF systems.
Methodology: A bibliographic study was conducted to investigate the applications of the Z-Transform across various engineering fields, including control systems, automation, biomedical signal processing, and telecommunications. Additionally, a MATLAB simulation of the Goertzel Algorithm was performed and compared with the traditional Fast Fourier Transform (FFT) to evaluate its performance in detecting DTMF tones.
Results: The study reveals several applications of the Z-Transform, and the simulation demonstrates that the Goertzel Algorithm is more efficient than FFT in terms of processing and detecting DTMF tones.
Conclusion: The Goertzel Algorithm is identified as an efficient implementation of the Z-Transform for DTMF detection in telecommunications. It provides a viable alternative to the FFT in terms of computational efficiency, especially when dealing with a limited number of frequencies.
Originality: This study combines a comprehensive literature review on the Z-Transform and Goertzel Algorithm, with a comparative analysis of their efficiency in DTMF detection, offering new insights into their practical applications.
Limitations: The simulation was limited to a small set of frequencies, and further research is needed to assess the algorithm’s performance in more complex and dynamic scenarios.
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[1] X. Peng, J. Yin, and W. Zhi, “Sliding Z Transform: Applications to convolutive blind source separation,” College of Computer and Information, Hohai University, Nanjing, China, 2018. https://doi.org/10.48550/arXiv.1808.06553
[2] R. Garibay-Jiménez, “La Transformada Z,” Facultad de Ingeniería, Universidad Nacional Autónoma de México, 1997. [Online]. Available: https://dctrl.fi-b.unam.mx/ricardo/Transformada%20Z/La%20Transformada%20Z_corregido.pdf
[3] G. C. Rodríguez, La Transformada Z: Caracterización de señales digitales en el dominio z, caracterización de sistemas LTI digitales mediante su función de transferencia, 2019. [Online]. Available: https://dademuch.com/wp-content/uploads/2020/04/la-transformada-z.pdf
[4] D. Jyoti and K. Prasad, “Study of Z-Transform,” International Journal of Creative Research Thoughts (IJCRT), vol. 9, no. 8, 2021.
[5] H. N. Apolo-Castillo and A. E. Córdova Medina, “Modelación matemática y simulación de un filtro digital híbrido FIR adaptativo lineal óptimo,” undergraduate thesis, Universidad Politécnica Salesiana, Ecuador, 2010.
[6] M. Paz, O. Rodríguez, and C. Galasso, “Uso de la placa Discovery para el cálculo e implementación de filtros FIR e IIR,” in 19º Concurso de Trabajos Estudiantiles (EST 2016), 2016.
[7] E. Cheng and P. Hudak, “Audio Processing and Sound Synthesis in Haskell,” Department of Computer Science, Yale University, 2009.
[8] J. Edwards, Frequency Domain Theory and Applications, DSP Numerix. [Online]. Available: https://www.numerix-dsp.com/appnotes/FrequencyDomainProcessing.pdf
[9] W. M. Gentleman, “An error analysis of Goertzel’s (Watt’s) method for computing Fourier coefficients,” The Computer Journal, vol. 12, no. 2, pp. 160–165, 1969. https://doi.org/10.1093/comjnl/12.2.160
[10] D. Dorran, “The z-transform: A practical overview,” 2023. http://dx.doi.org/10.13140/RG.2.2.17864.49926
[11] D. López and E. Obregón, “La transformada Z,” Revista Colombiana de Matemáticas, vol. 8, no. 3, 1966.
[12] N. A. Rondón, “La Transformada Z y algunas aplicaciones,” undergraduate thesis, Escuela de Matemáticas, Facultad de Ciencias, Universidad Industrial de Santander, Colombia, 2005.
[13] Y. Gui, J. Wang, F. Jin, C. Chen, and M. Xia, “Development of a family of explicit algorithms for structural dynamics with unconditional stability,” Nonlinear Dynamics, vol. 77, no. 4, pp. 1157–1170, 2014. https://doi.org/10.1007/s11071-014-1368-3
[14] Y. Song, “A fractional PID controller based on particle swarm optimization algorithm,” Journal of Autonomous Intelligence, vol. 3, no. 1, pp. 1–7, 2020. https://doi.org/10.32629/jai.v3i1.94
[15] Y. Huang, C. Li, and X. Tian, “The Simulation of the Chirp-Z Transform Based on MATLAB GUI,” in Proc. 3rd Int. Conf. on Multimedia Technology (ICMT-13), 2013. http://dx.doi.org/10.2991/icmt-13.2013.7
[16] L. R. Rabiner and R. W. Schafer, “The Chirp Z-Transform Algorithm,” IEEE Trans. Audio Electroacoust., vol. 17, no. 2, pp. 86–92, 1969. https://doi.org/10.1109/TAU.1969.1162034
[17] J. Carceller, “Unidad de efectos de audio en Simulink,” undergraduate thesis, Universidad Politécnica de Madrid, Spain, 2014.
[18] Scitechdaily, “Engineers Solve 50-Year-Old Puzzle in Signal Processing – Inverse Chirp Z-Transform,” 2019. [Online]. Available: https://scitechdaily.com/engineers-solve-50-year-old-puzzle-in-signal-processing-inverse-chirp-z-transform/
[19] M. Abdullah, A. Gadir, A. Ageeb, and A. Suliman, “Transfer function and Z-transform of an electrical system in MATLAB/Simulink,” European Journal of Mathematics and Statistics, vol. 4, no. 3, pp. 9–20, 2023. https://doi.org/10.24018/ejmath.2023.4.3.190
[20] S. Yu and H. Chun, “Tensor z-Transform,” Journal of Applied Mathematics, vol. 2024, 2024. https://doi.org/10.1155/2024/6614609
[21] F. Caldarola, M. Maiolo, and V. Solferino, “A new approach to the Z-transform through infinite computation,” Communications in Nonlinear Science and Numerical Simulation, vol. 82, 2020. https://doi.org/10.1016/j.cnsns.2019.105019
[22] H. Wilf, “Gerald Goertzel (1920–2002), As I Knew Him,” University of Pennsylvania, 2004. [Online]. Available: https://www2.math.upenn.edu/~wilf/Gerald_Goertzel.html
[23] G. Goertzel, “An algorithm for the evaluation of finite trigonometric series,” The American Mathematical Monthly, vol. 65, no. 1, pp. 34–36, 1958. https://doi.org/10.2307/2310304
[24] B. Evans and J. Pinto, “Performance Evaluation and Real-Time Implementation of Subspace, Adaptive, and DFT Algorithms for Multi-tone Detection,” University of California, 2017. [Online]. Available: https://ptolemy.berkeley.edu/papers/96/dtmf_ict/www/paper.html
[25] A. Vitali, “The Goertzel algorithm to compute individual terms of the discrete Fourier transform (DFT),” STMicroelectronics, 2017. [Online]. Available: https://www.st.com/content/ccc/resource/technical/document/design_tip/group0/20/06/95/0b/c3/8d/4a/7b/DM00446805/files/DM00446805.pdf
[26] J. A. Cortés, J. A. Mendoza, and J. Muriel, “Alternativa al análisis en frecuencia de la FFT mediante el algoritmo Goertzel,” Scientia et Technica, vol. 16, no. 44, 2010.
[27] L. Malathi, A. Bharathi, and A. Jayanthi, “Review of fast complex multiplication algorithms and implementation,” Int. J. Curr. Eng. Sci. Res. (IJCESR), vol. 6, no. 5, 2019.
[28] T. Wang, H. Liu, W. Yao, W. Li, and R. Zhao, “Aliasing Suppression based on Sliding Goertzel DFT of Multisampling for Grid-tied Inverter with LCL Filter,” in Proc. IEEE Int. Power Electron. Appl. Conf. Expo. (PEAC), 2022. https://doi.org/10.1109/PEAC56338.2022.9959389
[29] R. G. Lyons, Understanding Digital Signal Processing, New Jersey: Prentice Hall, 2004.
[30] A. Oppenheim and R. Schafer, Discrete-Time Signal Processing, 3rd ed., New Jersey: Prentice Hall, 1998.
[31] C. Yeh and S. Hwang, “Efficient Detection Approach for DTMF Signal Detection,” Appl. Sci., vol. 9, no. 3, 2019. https://doi.org/10.3390/app9030422
[32] W. Elmenreich, “Efficiently detecting a frequency using a Goertzel filter,” 2011. [Online]. Available: https://netwerkt.wordpress.com/2011/08/25/goertzel-filter/
[33] R. Hernández Sampieri, C. Fernández Collado, and P. Baptista Lucio, Metodología de la investigación, México: McGraw-Hill, 2010.
[34] S. Sreeja and A. Sanyasi, “Generation and detection of dual tone multi-frequency (DTMF) signals,” Int. J. Manage. Technol. Eng., vol. 13, no. 4, 2023.
[35] A. C. Vidyashree, G. Bhagyashri, and N. Kumar, “DTMF Detection from Goertzel’s Algorithm,” Int. J. Eng. Res. Electron. Commun. Eng. (IJERECE), vol. 3, no. 5, 2016.
[36] M. M. Gonzáles-Baldeón, Diseño e implementación de un controlador PID discreto en controladores lógicos programables, thesis, Faculty of Industrial, Systems and Computer Engineering, Universidad Nacional José Faustino Sánchez Carrión, Perú, 2022.
[37] W. Bolton and F. Ramírez, Ingeniería de control, México: Alfaomega, 2001.
[38] R. E. Kalman, “Mathematical description of linear dynamical systems,” J. SIAM Control, vol. 1, no. 2, 1963. https://doi.org/10.1137/0301010
[39] V. Artemyev, S. Mokrushin, S. Savostin, A. Medvedev, and V. Pankov, “Processing of time signals in a discrete time domain,” Machine Science, vol. 12, no. 1, 2023. https://doi.org/10.61413/FRCR4965
[40] D. Reyes-Gonzáles and M. Sánchez-Marchena, Diseño de un sintonizador para controladores PID aplicados a sistemas eléctricos de primer orden, thesis, Faculty of Engineering, Universidad Privada Antenor Orrego, 2017.
[41] I. C. Morales, Automatización de un sistema de control para el circuito de flujo termodinámico de un colector solar tipo cilindro–parabólico, thesis, Universidad Politécnica de Puebla, 2017.
[42] O. Abodena, “Robust and high-capacity audio watermarking based on Chirp Z-Transform,” in Proc. 29th Signal Process. Commun. Appl. Conf. (SIU), 2021. https://doi.org/10.1109/SIU53274.2021.9477976
[43] L. J. Arcos Pantoja and J. M. Calderón Chávez, “Implementación De Filtros Digitales Tipo FIR En FPGA’S Con Coeficientes Reconfigurables ON-LINE,” Hallazgos, vol. 1, no. 2, 2004. https://doi.org/10.15332/s1794-3841.2004.0002.11
[44] M. Diarra, X. Zhao, X. Wu, I. Nketsiah, Y. Li, and H. Zhao, “Induction Motors Speed Estimation by Rotor Slot Harmonics Frequency Using Zoom Improved Chirp-Z Transform Algorithm,” Energies, vol. 15, no. 21, 2022. https://doi.org/10.3390/en15217877
[45] A. Rashid, S. Abed, and O. Hasan, “Formal analysis of 2D image processing filters using higher-order logic theorem proving,” EURASIP J. Adv. Signal Process., vol. 2022, 2022. https://doi.org/10.1186/s13634-022-00882-3
[46] J. C. Delgado, Control óptimo lineal para la refrigeración de un motor de combustión interna, MSc. thesis, Universidad Rafael Belloso Chacín, 2014.
[47] T. Palleja, A. Vela, M. Ribes, J. Moreno, J. Pablo, and F. Sancho, “Didactic platform for DC motor speed and position control in Z-plane,” ISA Trans., vol. 118, pp. 116–132, 2021. https://doi.org/10.1016/j.isatra.2021.02.020
[48] D. M. Rojas-Vallejo, Desarrollo de una estrategia de control predictivo aplicado a un péndulo invertido, que permita la estabilización de imágenes en robots para exploración agrícola, Faculty of Engineering, Universidad La Salle, Colombia, 2018.
[49] H. Guo, H. Cao, K. Yang, and Z. Zhang, “Precise measurement of human heart rate based on multi-channel radar data fusion,” Sheng Wu Yi Xue Gong Cheng Xue Za Zhi, vol. 41, no. 3, 2024. https://doi.org/10.7507/1001-5515.202307010
[50] M. Martínez, R. Nápoles, V. Acevedo, and R. Quiñones, “Estabilidad de los parámetros cuantitativos del Electroencefalograma en atletas de boxeo,” Rev. Cubana Med. Deporte Cult. Física, vol. 16, no. 2, 2021.
[51] G. A. Cerda and L. Morales, “Comparación de las técnicas de detección de cruce por cero y la transformada Z-Chirp para medir frecuencias en el rango ultrasónico,” Pistas Educativas, vol. 39, no. 128, 2018.
[52] T. Aydemir, M. Sahin, O. Aydemir, “Determination of hypertension disease using chirp z-transform and statistical features of optimal band-pass filtered short-time photoplethysmography signals,” Biomed. Phys. Eng. Express, vol. 6, no. 6, 2020. https://doi.org/10.1088/2057-1976/abc634
[53] A. Pérez, G. La Mura, R. Piotrkowski, E. Serrano, “Procesamiento no lineal con Wavelet para la eliminación del ruido en imágenes planares de medicina nuclear,” Bioing. Fís. Méd. Cuba, vol. 3, no. 2, 2002.
[54] C. Ciulla, “Pulse-transfer function of the intensity-curvature functional: Applications in magnetic resonance angiography of the human brain,” Innov. Emerg. Technol., vol. 9, 2022. https://doi.org/10.1142/S2737599422500013
[55] K. Singh, S. Hsieh, C. Swarup, T. Singh, “Authentication of NIfTI Neuroimages Using Lifting Wavelet Transform, Arnold Cat Map, Z-Transform, and Hessenberg Decompositionrg,” Trait. Signal, vol. 3, no. 1, 2022.
[56] I. Boukli-Hacene, “Hybrid Gray scale & color medical images compression by Quincunx wavelets and Walsh Hadamard transform,” Research Square, 2023. https://doi.org/10.21203/rs.3.rs-2947469/v1
[57] J. Yang, Z. Qin, Q. Zhang, T. Yang, “Research on Modulation Mode Identification of PSK Signal Based on M-th Power Spectrum Features,” in Proc. 2022 ICWOC, 2022. https://doi.org/10.1109/ICWOC55996.2022.9809871
[58] Q. Wang, “Digital signal processing oriented Electronic communication Engineering applications and Practices,” Cuad. Desarro. Apl. TIC, vol. 13, no. 1, 2024. https://doi.org/10.17993/3ctic.2024.131.96-115
[59] B. Tang, J. Zhang, S. Hu, B. Xu, H. Zhan, “Low Complexity Two-Stage FOE Using Modified Zoom-FFT for Coherent Optical M-QAM Systems,” IEEE Photon. Technol. Lett., vol. 32, no. 5, 2020. https://doi.org/10.1109/LPT.2020.2969701
[60] I. Kubiak, A. Przybysz, “Fourier and Chirp-Z Transforms in the Estimation Values Process of Horizontal and Vertical Synchronization Frequencies of Graphic Displays,” Appl. Sci., vol. 12, no. 10, 2022. https://doi.org/10.3390/app12105281
[61] E. Sandoval Robayo, “Sistema de detección de situaciones delictivas en establecimientos comerciales usando inteligencia artificial”, thesis, Universidad Técnica de Ambato, Ecuador, 2024.
[62] M. Prieto, “Análisis y caracterización de los sistemas LTI usando la Transformada Z”, 2013. [Online]. Available: http://lcr.uns.edu.ar/fvc/NotasDeAplicacion/FVC-ManuelPrieto.pdf
[63] G. Millán, G. Fuertes, M. Alfaro, R. Carrasco, M. Vargas, “A Simple and Fast Algorithm for Traffic Flow Control in High-Speed Computer Networks”, in Proc. ICA-ACCA, 2018. https://doi.org/10.1109/ICA-ACCA.2018.8609857
[64] M. A. Acevedo-Mosqueda, V. R. Alanis-Cho, M. Sánchez-Meraz, “Filtro inverso de un sistema de radiocomunicación en HF”, Científica, vol. 14, no. 3, 2010.
[65] M. González-Blanco, “Contribución a la cancelación de errores en medida de antenas en campo próximo mediante técnicas de filtrado”, PhD. Thesis, Universidad Politécnica de Madrid, 2018. https://doi.org/10.20868/UPM.thesis.53268
[66] G. Millán Naveas, M. Vargas Guzmán, “Un algoritmo de control de flujo para redes de computadoras de alta velocidad”, Ingeniare, vol. 28, no. 1, 2020. https://doi.org/10.4067/S0718-33052020000100024
[67] M. Ibrahim, “Complexity Reduction of Finite-Length MMSE Equalization Using FFT”, in Proc. NRSC, 2020. https://doi.org/10.1109/NRSC49500.2020.9235121
[68] Y. Tang, X. Zahng, “An Efficient Parallel Architecture for Resource-Shareable Reed-Solomon Encoder”, in Proc. SiPS, 2021. https://doi.org/10.1109/SiPS52927.2021.00035
[69] Q. Zhang, Z. Ge, Y. Hu, Y. Huang, “An encrypted speech retrieval algorithm based on Chirp-Z transform and perceptual hashing second feature extraction”, Multimed. Tools Appl., vol. 79, pp. 6337–6361, 2020. https://doi.org/10.1007/s11042-019-08450-y
[70] L. Regnacq, Y. Wu, N. Neshatvar, D. Jiang, A. Demosthenous, “A Goertzel filter-based system for fast simultaneous multi-frequency EIS”, IEEE Trans. Circuits Syst. II: Express Briefs, vol. 68, no. 9, pp. 3133–3137, 2021. https://doi.org/10.1109/TCSII.2021.3092069
[71] S. Nagakishore, P. Siddaiah, P. Ramana, “FFT based DTMF detection by using Spartan 3E FPGA”, Am. Int. J. Res. Formal, Appl. Nat. Sci., vol. 7, no. 1, 2014.
[72] A. Casanova-Vargas, J. P. Oviedo-Perdomo, E. E. Gaona-García, “Correction of the propagation model in digital terrestrial television networks in urban environments”, Vis. Electron., vol. 2, no. 1, pp. 145–158, 2019. https://doi.org/10.14483/22484728.18421
[73] B. Muntasher, A. Puttannavar, “Implementation of modified Goertzel algorithm using FPGA”, Int. J. Adv. Res. Eng. Technol., vol. 5, no. 10, 2014.
[74] N. Pamuk, Z. Pamuk, “Dual Tone Multi Frequency (DTMF) signal generation and detection using MATLAB software”, in UBT Int. Conf., 2015. https://doi.org/10.33107/ubt-ic.2015.97
[75] H. A. Eldednferia, J. R. Elbergali, “Performance Analysis of DTMF Detection using Modified Goertzel Algorithm over AWGN”, in Proc. CIT, 2017.
[76] M. M. Silva Zambrano, H. A. Romo Romero, J. M. Ramírez Viáfara, D. M. Galvis Zambrano, “Techniques for detecting voice fundamental frequency in real environments”, Ing. Solidar., vol. 13, no. 23, pp. 122–136, 2017. https://doi.org/10.16925/in.v23i13.2006
[77] S. Yang, S. Yuan, Y. Lin, I. Yang, “DTMFTalk: a DTMF-based realization of IoT remote control for smart-home elderly care”, Mob. Netw. Appl., vol. 27, pp. 196–207, 2022. https://doi.org/10.1007/s11036-020-01641-0
[78] A. Salinas Gonzalez, A. Escobar Díaz, H. Vacca González, “Technological transition from IPv4 to IPv6 at SNR: A success case”, Ing. Solidar., vol. 17, no. 2, pp. 1–28, 2021. https://doi.org/10.16925/2357-6014.2021.02.12
[79] Y. Li, Y. Zhang, Y. Wu, “Goertzel Algorithm Based on MATLAB Platform System Simulation for Listening Dial Tone Recognition Research”, in Proc. ICDPCS, 2023, pp. 114–121. https://doi.org/10.5220/0012150300003562
[80] P. Gregor, “Application of MUSIC algorithm to DTMF detection”, in Proc. TELSIKS, 2023. https://doi.org/10.1109/TELSIKS57806.2023.10315986
[81] F. Matango, “Digitalización de voz”, 2016. [Online]. Available: http://www.servervoip.com/blog/tag/digitalizacion-de-voz
[82] MathWorks, “DFT Estimation with the Goertzel Algorithm”. [Online]. Available: https://www.mathworks.com/help/signal/ug/dft-estimation-with-the-goertzel-algorithm.html




