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本文估算了PAM(脉冲幅度调制)接收机的误差概率。该接收机借助于同步电路从接收波形中可以获得符号定时。指出了估算误差概率的常规方法(使用同步电路的模-2π简化相位误差分布),没有考虑同步电路周期抖动的影响。提出了一个误差概率的正确表示式,即使用所谓的更新相位分布。此外,还就常规的和正确的误差概率推导了既简单又精确的近似表达式,它们清晰地说明了PAM接收机特性的影响,并指出,对于接收机输入端的递减的附加噪声电平,常规误差概率小得趋于零,而正确误差概率趋向于某个非零值,此值反比于抖动间的平均时间。因此,周期抖动给可达到的误差概率强加了一个有时还相当大的下限。
This article estimates the error probability of a PAM (Pulse Amplitude Modulation) receiver. The receiver can obtain the symbol timing from the received waveforms by means of a synchronization circuit. The conventional method of estimating the error probability (using modulo -2π to simplify the phase error distribution of the synchronization circuit) is pointed out without considering the effect of the periodic jitter of the synchronization circuit. A correct representation of the error probability is proposed, using so-called updated phase distributions. In addition, simple and precise approximations of the conventional and correct error probabilities are derived, which clearly illustrate the effects of the PAM receiver characteristics and indicate that for a decreasing additive noise level at the receiver input, The error probability tends to be small, and the correct error probability tends to some non-zero value, which is inversely proportional to the average time between jitter. Therefore, periodic jitter imposes a sometimes rather large lower bound on the error probability that can be reached.