Joint analysis of system delay window and target echo error for active cancellation of LFM signal

Aiming at the problem that the active echo cancellation system delay may decrease cancellation effect, this paper analyses cancellation effect for linear frequency modulation signal with joint consideration of system delay as well as amplitude error and phase error. The mathematical model is established based on the generation process of the cancellation signal. The expression of cancellation gain is derived according to the energy change of the echo signal after and before cancellation. By computer simulation, the relation between system delay and the cancellation effect as well as the influence of amplitude error and phase error are found. Simulation results show that to achieve good cancellation effect, the system delay should be controlled within several time windows which hasn't been mentioned by existing papers. Once the system delay is set, both amplitude error and phase error lower the cancellation effect.