数字低通滤波器和差分器(LPD)在生物信号的实时处理中是非常重要的。本文介绍了一种确定差分器系数的一般性方法,当已知信号及噪声的频谱时,即可得到最大的信噪比和最小的误差。虽然一般情况下并不是总可以得到信号和噪声频谱的先验知识,但在生物信号中.我们一般还是知道象ECG这样信号的谱估计.同时也知道ECG中嗓声的频谱.用这种先验知识对滤波器进行理论设计 Digital low-pass filters and differentiators (LPDs) are very important in the real-time processing of biological signals. In this paper, we introduce a general method to determine the difference coefficients. When the spectrum of the signal and noise is known, the maximum signal-to-noise ratio and the minimum error can be obtained. Although in general, prior knowledge of the signal and noise spectrum is not always available, in biological signals we generally know the spectral estimation of signals like ECGs and the spectrum of the noise in the ECG. Knowledge of the theoretical design of the filter