The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 23, 1980
Filed:
Jul. 31, 1978
Fumio Sugiyama, Sagamihara, JP;
Isao Tashiro, Kawasaki, JP;
Tokyo Shibaura Denki Kabushiki Kaisha, Kawasaki, JP;
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 operation period in which the above-mentioned reverse integration is carried out, the second input signal which is to be integrated for a length of time corresponding to the modulated pulse width of the first input signal is conducted to a second integrator to be integrated during the respective sampling periods. Each of the first and second integrators alternately carries out the integration and the reverse integration during the alternately recurring first and second unit operation periods following the aforesaid ones. A counter counts a number of clock pulses issued for a length of time varying with the reverse integration applied each time. The number of clock pulses thus counted are added in succession, thereby determining a cumulatively added sum of the multiplication products of the first and second input signals which corresponds to a watt-hour value.