Abstract: The accuracy of traditional method for amplitude detection based on auto-correlation is not high,and a new method for amplitude of weak sinusoidal signal in powerful noise based on dual-channel is introduced in this paper. According to the statistical properties of sinusoidal signal and noise Using synchronous sampling to get the amplitude information of original signal, and each factor which affects the result of the Algorithm is analyzed. The simulations proves its feasibility and effectiveness to detect the weak sinusoidal signal and having much higher resolution than auto-correlation method. So it has some practical value.

Key words: Weak signal, Amplitude detection, Multi-layer cross correlation