The researchers used wavelet transform and wavelet lifting to process signals from the stomach (EGG) in order to diagnose gastric diseases. They analyzed signal energy and entropy to choose the best wavelet functions for filtering the signals. By filtering EGG signals with different wavelet functions, they successfully separated slow waves and spike waves. The experimental data confirmed that wavelet transform and wavelet lifting are effective methods for filtering EGG signals, providing a useful tool for diagnosing and measuring gastric diseases.