The Design Of The Hardware Module For The Echo Canceller Test System

The echo cancellers are widely used in the telecom system to effectively improve the quality of the communication. It is important for acquiring the performance of the canceller by carrying out all kinds of tests which are defined in the ITU's G.165, G.167, G.168 standards, and achieve the corresponding result.This thesis introduces the hardware module of an echo canceller test system which is designed to follow on the ITU's G.165, G.167, G168 standards to achieve the performance of the canceller by providing the high SNR output test signal to the canceller and sampling it's output accurately. According to the characteristics and requirements of the test progress, the hardware circuit is designed base on the C5509 DSP, combined with the AIC23 codec to ensure the precision of the test result. This thesis puts forward a layered design scheme on the test software, and has finished the encapsulation on the operation flows of low layer hardware to make it more easier to design the upper layer test program. By using the "USB Bootload" mode, the system can on-line change and maintain the test software, achieve high facility and high expansibility.