| 摘要 |
An electricity metering transducer which samples voltages and currents at an innerconnection terminal (10) of an electrical energy distribution system, converts those samples to digital form and computes selected electricity metering quantities. In a multiphase system current and voltage signals are multiplexed to a pair of codecs (24 & 26), one for current signals and one for voltage signals. The period of the signals being sampled is detected and used to generate a substantially nonsynchronous sampling signal so that a sample migration system is created which provides a large number of samples of a composite waveform. The steps of a digitally generated stepwise approximation of a sawtooth waveform are summed with the sequential analog samples and then removed from the digital value of each sample by software operation in order to increase the resolution of the digital to analog conversion. |
