<![CDATA[ABSTRAKHaemorrhoidal artery ligation (HAL) adalah metode operasi wasir yang memiliki keunggulan rasa sakit minimal dan waktu pemulihan cepat. Prosedur HAL bergantung pada bunyi Doppler untuk menentukan letak arteri dalam liang anus. Derau yang tercampur dalam sinyal membuat dokter kesulitan mendengarkan bunyi Doppler yang menandakan letak arteri wasir. Adaptive line enhancer (ALE) dengan algoritma least mean square (LMS) digunakan dalam penelitian ini untuk mengurangi aras derau yang terkandung dalam sinyal bunyi Doppler aliran darah. Hasil simulasi menunjukkan parameter mean square error (MSE), signal to noise ratio (SNR), dan waktu eksekusi untuk berbagai orde tapis. Nilai maksimum power spectral density (PSD) sinyal yang masuk ke tapis -86 dB/Hz, kemudian turun menjadi -101 dB/Hz setelah lewat tapis. SNR tertinggi 40,03 dB didapat ketika orde tapis 16. Waktu eksekusi hampir tidak berubah meskipun orde filter dinaikkan.Kata kunci: pengurangan derau, bunyi Doppler, ALE, LMS, HAL ABSTRACTHemorrhoidal artery ligation (HAL) is one of surgical methods in treating hemorrhoids disease known for less pain and fast recovery. HAL procedure relies on the Doppler audible sound to locate arteries within rectal column. Noise interfering the signal of interest makes arteries detection becomes difficult task for the surgeon since signal and noise spectral overlaps. Adaptive line enhancer (ALE) with least mean square (LMS) algorithm is used in this study to reduce noise level contained in Doppler blood flow sound signal. The simulation results show the mean square error (MSE), signal to noise ratio (SNR), and execution time for different filter order. The maximum power spectral density (PSD) value of the noisy signal and filtered signal are -86 dB/Hz and -101 dB/Hz. respectively. The highest SNR of 40.03 dB is obtained when filter tap order is set to 16. However signal processing time remains almost unchanged as the filter tap order increased.Keywords: noise reduction, Doppler sound, ALE, LMS, HAL]]>
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