Arithmetic operation apparatus for an electronic watt-hour meter
US4224671A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1978 |
| Grant date | Sep 23, 1980 |
| Priority date | — |
| Expiry date | Jul 31, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06G7/161
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is an arithmetic operation apparatus for an electrical watt-hour meter for cumulatively adding products arrived at by multiplying two input signals in succession which correspond respectively to a line voltage and line current. The apparatus comprises a pulse width modulator for modulating a first input signal of line voltage into the form of a pulse width for each sampling period. A certain number of the sampling periods is taken as a first arithmetic operation period (hereinafter referred to as "a first unit operation period"). During the first unit operation period, a second input signal of line current is supplied for a length of time corresponding to each modulated pulse width of the first input signal. The second input signals thus supplied are integrated by a first integrator during each first unit operation period. During a succeeding operation period consisting of the same specified number of sampling periods (hereinafter referred to as "a second unit operation period"), a reference signal which has a polarity opposite to that of the integrated signal at the end of the first unit operation is reversely integrated by the first integrator. During the second unit op…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.