A simple and accurate FPGA-based synchronizing method for power-line signal acquisition

摘要

Power-line signal analysis according to international standards implies the acquisition of signals with a stable frequency. However, the value of this frequency falls in a relatively wide range. That frequency stability allows the adoption of an acquisition scheme where it is not allowed to use another window function other than the rectangular one. This implies that the signal sample set has to include an integer number of periods of the analyzed signal. Otherwise, a significant spectral leakage is produced during the sample set processing. If it is also taken into account that the fundamental analysis tool, FFT, needs a sample set with a number of points that has to be a power of two, it must be concluded that signal samples has to be acquired in a synchronized way with the signal, or a lot of preprocessing has to be done before FFT in order to obtain a sample set that fulfills the mathematical and standard-derived requirements. In this paper we present and evaluate a simple and accurate FPGA-based synchronizing method that allows the right acquisition of power-line signals.