Five-Point Amplitude Estimation of教材.pdf

IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 59, NO. 3, MARCH 2010 623
Five-Point Amplitude Estimation of
Sinusoidal Signals: With Application
to LVDT Signal Conditioning
Shang-Teh Wu and Jyun-Lang Hong
Abstract—A simple algorithm for the amplitude estimation of si- to calculate the amplitude. If the frequency of the signal is
nusoidal signals is proposed. It is first shown that three well-spaced accurately known, three consecutive samples will suffice to
samples are sufficient to calculate the amplitude of a harmonic obtain the amplitude of the sinusoid. The ideal sampling rate
signal. However, the three-point estimator is sensitive to deviation
of the sampling rate. To deal with errors that were caused by is three times the signal frequency. To deal with errors that
noncoherent sampling, a modified algorithm that uses two more were caused by noncoherent sampling (., deviation of the
samples is developed. With the five-point algorithm, estimation sampling rate from an integer multiple of the signal frequency),
errors fall below % for 1% of frequency deviation. As a a modified algorithm that is based on five consecutive sam-
demonstration of its simplicity, the five-point estimator is applied ples is developed. With the five-point algorithm, estimation
to the signal conditioning of a linear variable differential trans-
former (LVDT) using moderat