Research Article PLI Cancellation in ECG Signal Based on Adaptive Filter by Using Wiener-Hopf Equation for Providing Initial Condition Anchalee Manosueb, Jeerasuda Koseeyaporn, and Paramote Wardkein Telecommunications Engineering Department, Faculty of Engineering, King Mongkut’s Institute of Technology Ladkrabang, Chalongkrung Road, Ladkrabang, Bangkok 10520, Tailand Correspondence should be addressed to Anchalee Manosueb; anchalee.manosueb@gmail.com Received 3 May 2014; Accepted 29 June 2014; Published 23 July 2014 Academic Editor: Carlo Cattani Copyright © 2014 Anchalee Manosueb et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tis paper presents a technique for fnding the optimal initial weight for adaptive flter by using diference equation. Te obtained analytical response of the system identifes the appropriate weights for the system and shows that the MSE depends on the initial weight. Te proposed technique is applied to eliminate the known frequency power line interference (PLI) signal in the electrocardiogram (ECG) signal. Te PLI signal is considered as a combination of cosine and sine signals. Te adaptive flter, therefore, attempts to adjust the amplitude of cosine and sine signals to synthesize a reference signal very similar to the contaminated PLI signal. To compare the potential of the proposed technique to other techniques, the system is simulated by using the Matlab program and the TMS320C6713 digital board. Te simulation results demonstrate that the proposed technique enables the system to eliminate the PLI signal with the fastest time and gains the superior results of the recovered ECG signal. 1. Introduction Nowadays, the number of patients with cardiac disorders continuously increases. Certain inappropriate habits in daily life, such as low physical activity, can lead to the risk factors for heart disease. Moreover, the improper eating habits might cause hyperlipidemia, incurrent disease of hypertension, and diabetes. Tere are several forms of cardiac disorder, for instance, coronary heart disease, enlarged heart, valvular heart disease, and myocardial disease due to myocardial infarction. Te detection of these symptoms commonly relies on medical professionals to diagnose various factors to identify the exact abnormality of the patient’s heart. Te electrocardiogram (ECG) signal is a periodic waveform, which represents electrical occurrences during one heartbeat. Terefore, the interpretation of the ECG waveform is one basic technique that is used in the diagnosis of cardiac disorders. If an abnormality exists in the ECG waveform, it implies that the heart is also functioning abnormally; then, an in-depth diagnosis should be conducted. Te ECG signal is a voltage signal that occurs in cardiac myocyte; it results from the exchange of the mineral concentration, such as sodium ions outside and potassium ions inside the cell. Te amplitude of the ECG signal is typically very small (less than 20 mV). In the measurement of the ECG signal, the electrical device, which consists of several circuits, is used to acquire the signal. Although digital signal processing is applied through the process of signal acquisition [1–4], unfortunately, the acquired ECG waveform is still contaminated by the power line interference (PLI). If the PLI’s amplitude is greater than 1% of the ECG’s amplitude, it may afect the diagnosis of the medical professionals. According to the mentioned information, the PLI signal usually occurs during the processes of ECG signal acquiring. It distorts the ECG waveform and causes the difculties in the diagnosis procedure. By reviewing the existing literature, various methods for cancelling the PLI signal had been proposed. For example, the method which was proposed by Levkov et al. [6] generates the reference PLI signal by delaying the contaminated signal. Tis means that the reference PLI signal and the contaminated PLI signal have equal frequency and amplitude, but diferent phase. Ten, the PLI cancellation Hindawi Publishing Corporation Computational and Mathematical Methods in Medicine Volume 2014, Article ID 471409, 11 pages http://dx.doi.org/10.1155/2014/471409