Pre-kompensasi Respon Saluran Transmisi pada Jaringan Akses Multimedia ADSL 1,6 Mbps
Keywords:
jaringan akses, kompensasi, access network, ADSL, compensation, equalization, multimedia,Abstract
Sari. Berkembangnya pola kehidupan masyarakat semakin meningkatkan kebutuhan akan layanan yang mudah dan cepat, seperti jaringan akses multimedia. Salah satu kelompok sistem xDSL yang merupakan teknologi jaringan akses alternative adalah 16-QAM-ADSL. Masalah utama yang dihadapi dalam sistem Xdsl adalah memperkecil pengaruh respons saluran transmisi, yang umumnya dapat menggunakan equalizer. Pre-kompensasi respons saluran transmisi dapat ditambahkan untuk membantu kerja equalizer. Pre-kompensasi adalah sebuah filter yang ditambahkan sebuah ADC untuk kompensasi awal respons saluran transmisi. Penggunaan pre-kompensasi dapat memperpendek panjang koefisien equalizer menjadi sekitar 20 tap, yang apabila tanpa pre-kompensasi memerlukan sampai 100 tap. 16-QAM-ADSL dapat mencapai kapasitas 1,6 Mbps (TI/DSI pada 1,544 Mbps) pada saluran sejauh 18 kft. 26 AWG. Sistem transceiver 16-QAM-ADSL yang diteliti di sini dapat bekerja dengan baik setelah melakukan pelatihan selama 0,25 detik. Kesalahan fasa sampling sekitar 7,2 derajat dan frekuensi sampling sekitar 10kHz.
Transmission Channel of Pre-compensation Response in the ADSL 1.6M bps Multimedia Access Network
Abstract. The development of the living pattern of society has increased the needs of faster and easier services, such as multimedia access network. One of the xDSL family, as an alternative to the network access technology, is the 16-QAM ADSL. The main problem in xDSL is reducing the transmission channel response which usually can be accomplished by using an equalizer. Transmission channel of pre-compensation response can be added to assist the work of the equalizer. A pre-compensation is a filter which has been added before ADC to compensate the earlier response of the transmission channel. The utilization of the pre-compensation can reduce the length of the equalizer coefficients from 100 tap to 20 tap. The 16-QAM ADSL can reach the capacity of 1.6M bps (TI/DSI 1.544Mbps) in a 18 kft channel 26 AWG. The 16-QAM ADSL transceiver system which is explored in this study has worked well after 0.25 second training period. The sampling phase error is about 7.2 and the sampling frequency error is about 10 Khz.
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