1. baseline noise: in the absence of signal input, record the data measured or collected by baseline, analyze the data, observe the variation and fluctuation range between the data, and quantify the noise level by statistical methods (such as mean and standard deviation).

2. Baseline drift: record the data measured or collected by the baseline in a continuous period of time, analyze the data, observe the overall trend and change of the signal, and estimate the drift rate or trend of the baseline by statistical methods or other mathematical models.