Improved system for measuring the period of a quasi-periodic signal

摘要

The disclosed system for measuring the periodic content of an input signal includes an autocorrelation function generator for generating a sequence of autocorrelation functions. Each of the autocorrelation functions is representative of an autocorrelation function of a portion of the input signal. The system further includes a temporal filter for filtering the autocorrelation functions and thereby generating a lag histogram. In other forms the system may comprise a fetal heart rate monitor for measuring the heart rate of a fetus in vivo. The monitor generates a lag histogram and uses the lag histogram for stabilizing the determination of the fetal heart rate.