Echo cancellation is a classic problem in DSP and digital communication. Adaptive echo cancellation is an application of adaptive filtering to the attenuation of undesired echo in the telecommunication network. This is accomplished by modeling the echo path using an adpative filter and subtracting the estimated echo from the echo-path output. In this project, the concept of echo cancellation and echo cancellation systems are studied, simulated, and implemented in Matlab and TI TMS3206C6711 DSK. The LMS, NLMS. Fast block LMS and RLS algorithm and investigated for echo canceller and two double talk detection algorithm are presented and combined with NLMS adaptive algorithm against double talk. Finally the adaptive echo cancellation system successfully developled by the NLMS and normalized cross-correlation DTD algorithms meet the general ITU G. 168 requirements and show excellent robustness against double talk.