Comparison plots between single-exposure spectra and coadded spectra. The parameters of single-exposure spectra are the weighted average of T_eff and log g obtained from each single-exposure spectrum, using the S/N as the weight. The parameters of coadded spectra are from wdtools fitting. The left panel shows T_eff, while the right panel displays log g. And T_eff shows a mean difference of −75 K with a standard deviation of 561 K, while log g has a mean difference of −0.04 and a standard deviation of 0.11.