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技術論壇 |
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回音消除器在嵌入式系統上之設計與分析Design and Analysis of Echo Canceller on Embedded System
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中文摘要 |
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當使用者使用免持式模式進行通話時，由喇叭放出的聲音會被麥克風所捕捉，造成回音，對通話中的使用者造成困擾。隨著積體電路效能越來越強，利用可調適濾波器實現回音消除已是被廣為使用的技術。在嵌入式系統中，中央處理器及記憶體等資源有限，如何將資源做有效的利用是個重要的課題。本文將介紹回音消除器的原理及其實作方法，並考量到如何在效能與有限資源之間，取得一個可接受的平衡點。 |
| Abstract |
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In hands-free mode, the signal radiated from the loudspeaker will be
picked up by the microphone, which produces echoes, will disturb users. Due to
the evolution of the integrated circuit, echo cancellation based on adaptive
filter is publicly employed. On embedded system, the resource, for example, CPU
and memory, is limited. It is an important issue that how to used resource
efficiently. This text will introduce the principles and implementation of echo
canceller, and the tradeoff between the performance and the cost. |
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作者：鍾國煌
Kuo-Huang Chung |
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下世代IP多媒體子系統之即時訊息服務技術3GPP IMS Messaging Service Technology
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中文摘要 |
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下世代3G/B3G/NGN無線通訊或有線寬頻之核心網路架構將演進成為全部利用IP技術之All-IP網路，其中整個核心網路之IP多媒體子系統(IP
Multimedia
Subsystem；IMS)將採用SIP技術作為各異質網路間的通訊標準協定，以進行話務控制，並支援與上層應用伺服器(Application
Server)溝通，成為服務控制平台，以提供即時語音/視訊通訊、線上狀態與即時訊息等多樣化的應用加值服務；3GPP在制定IMS-based的即時訊息
服務時，即採用SIP/SIMPLE作為該服務標準化的討論與制定，以規範出整體服務的需求、架構、功能和實作之依循標準。本文即針對3GPP所規範架構於IMS之上的即時訊息服務技術作一詳細介紹，並對其相關應用服務加以說明。 |
| Abstract |
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The future Telecom networks 3G/B3G/NGN, whether wireless core
networks or wired broadband networks, will converge to an All-IP Network. Its
core network IP Multimedia Subsystem leverages SIP technology as the
communication signaling protocol between heterogeneous networks for
call/session control and between S-CSCF and Application Server for offering
real-time communication service, e.g. voice/video, presence, and instant
messaging service, etc. 3GPP is working on IMS-based messaging service
specification based on SIP/SIMPLE technology, specifying the service
requirement, architecture, functionality and implementation. This article is to
introduce the technologies and related services on the 3GPP IMS-based messaging
service. |
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作者：何哲勳 Che-Shiun Ho、沈婉婉 Wan-Wan
Shen 、沈惠如 Hui-Ru Shen |
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