| 摘要 |
<p>An electricity meter for the measurement of electrical energy (1) supplied to a consumer (2) comprising a first measurement circuit (3) which produces a first analogue signal the amplitude of which is representative of supplied current, a second measurement circuit (4) which produces a second analogue signal representative of supplied voltage, a triangular waveform reference signal generator (14) , two comparators (10,13) to which said first and second analogue signals respectively and the triangular waveform reference signal are fed so that the comparators each produce a pulse-width modulated output signal characteristic of current and voltage respectively, the mark/space ratio of which is determined in dependance upon the amplitude of the analogue signal fed thereto, the output signals each being repeatedly sampled to produce in respect of voltage and current, during consecutive periods corresponding to each cycle of the triangular waveform reference signal a plurality of samples, corresponding current and voltage samples for each period being mutually multiplied and integrated thereby to provide a signal indicative of energy supplied. <IMAGE></p> |
