说明：  针对有多个信号(线谱)情况下的“背景噪声”均值估计，在上述算法的基础上进一步提出了排序截断平均算法(Order-Truncate-Average Algorithm)。
(In order to estimate the mean value of "background noise" with multiple signals (line spectrum), an order truncated average algorithm (order truncate average algorithm) is proposed based on the above algorithm.)