Performance improvement of adaptive echo canceller using block techniques

Dissertant

Ayyub, Ayman F.

University

University of Technology

Faculty

-

Department

Department of Electrical Engineering

University Country

Iraq

Degree

Master

Degree Date

2006

English Abstract

The evolution of telecommunication network toward the integrated services network is being accelerated by development of digital transmission techno Quest and switching equipment.

In order to provide two wire ISDN Basic Rate Access {BRI) which consist of 2B'D channels D channel for digitized voice or high speed data (64kbps) and D channel for signaling and low speed data (16k fops 11.

the BRI itself required <48KbpsJ of operating overhead, the full duplex transmission of the BRI will be the summation of these channel {2B+D} and the overhead bits to form one digital pipe of (192Kbps).

in telephone connection Thai involve the use of both four wire and two wire transmission ,an echo of transmitted signal is generated at the hybrid that connect the four wire part to the two wire part of the trans mission.

The echo represents an impairment that can be annoying subjectively as more obvious impairment of low volume and noise.

When the telephone network is used for data transmission {digital transmission) the same echoes that encountered in speech transmission are occurred.

To overcome this problem, several techniques arc used one of them is the echo canceller by using the adaptive filter and several algorithm is applied to the adaptation process of this filter some of they are out the scope of this thesis.

The thesis foe used on o^ of the most popular algorithm thrall used in the acoustic application called least mean square (LMS), and exam this algorithm on special type of line encoder called two binary one quaternary UUKJ), test its Performa Eire and attenuation.

Also some of its modifications as normalize LMS.

Variable step size LMS and variable step size lazed LMS.

Then take a special type of its modification called block ^S or the (RIMS) showing its pool- performance under this type of line idler(2BlQ}, and proposing a new modification that has low number of fixation per sample, very good puffin mince, faster in learning than BLMS but slower than LMS, and maintain a good ratio of attenuation.

Propose new filter algorithm contain two layer one of them are hidden, that show very good performance for very high filter taps, also has a good ratio of attenuation.

Main Subjects

Electronic engineering

Topics

• Data processing
• Digital communications

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-306013