实现小波变换调用upcoef 函数，根据近似（低频）分量和细节（高频）分量进行重构-Wavelet transform to achieve upcoef function call, according to approximation (low frequency) component and details (high frequency) component is reconstructed

三个函数信号叠加，进行小波分解，提取近似信号与原信号比较-Superposition of three functions signals, wavelet decomposition, similar to the signal extraction compared with the original signal