| 摘要 |
Metering kWh in a single-phase, two-wire, fL hertz, electrical system is accomplished by multiplying analog signals representing line current and voltage so as to produce a series of width-and-amplitude modulated pulse signals, each representing instantaneous power in the system during a sampling interval TS = 1fS; TL = 1/fL being much greater than TS. The series of modulated pulse signals is converted in, for example, a low-pass filter to a signal having an amplitude representative of average power. An analog-to-pulse rate converter is used for converting the signal representing average power to another series of output pulse signals having a variable signal repetition rate f proportional to average power, each output pulse signal representing a constant, or quantized, amount of electrical energy. A stepping switch and register performs conventional accumulation, storage and display functions in response to said series of output pulse signals delivered thereto.
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