US4752731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic type electric energy meter
Assignee: Mitsubishi Electric Corp
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Filing: 1986-06-13
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Granted: 1988-06-21
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Expires: 2006-06-13
Abstract
Abstract An electronic type electric energy meter comprising an analog adder and an analog subtracter by which signals proportional to a voltage and a current of a circuit to-be-measured are respectively added and subtracter therebetween, A/D converters which convert outputs of the analog adder and the analog subtracter into digital values, and an arithmetic control unit by which the digital values from the A/D converters corresponding to the analog addition value and subtraction value are respectively squared so as to obtain a difference of the squared values, and the difference is accumulated thereby to measure electric energy. The values of the input analog voltages of the A/D converters vary in only narrow ranges, so that the electric energy can be calculated at high precision in a wide current variation range by means of the A/D converters having small numbers of bits.
Inventors
- 👤 Masayoshi Toda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:35
CPC Classifications
G; G01; G01R; G01R21/00; G01R21/133
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
98 words
An electronic type electric energy meter comprising an analog adder and an analog subtracter by which signals proportional to a voltage and a current of a circuit to-be-measured are respectively added and subtracted therebetween, A/D converters which convert outputs of said analog adder and said analog subtracter into digital values, and an arithmetic control unit by which the digital values from said A/D converters corresponding to the analog addition value and subtraction value are respectively squared so as to obtain a difference of the squared values, and by which the difference is accumulated to thereby measure electric energy.
Claim 2
Dependent Claim
98 words
An electronic type electric energy meter comprising an analog adder and an analog subtracter by which signals proportional to a voltage and a current of a circuit to-be-measured are respectively added and subtracted therebetween, A/D converters which convert outputs of said analog adder and said analog subtracter into digital values, and an arithmetic control unit by which the digital values from said A/D converters corresponding to the analog addition value and subtraction value are respectively squared so as to obtain a difference of the squared values, and by which the difference is accumulated to thereby measure electric energy.
Claim 3
Dependent Claim
92 words
An electronic type electric energy meter comprising: analog means for providing first and second analog signals indicative of the sum and difference, respectively, of a voltage input and a current input; A/D converter means coupled to the analog means for converting the first and second analog signals to first and second digital signals; means coupled to the A/D converter means for generating a third digital value indicative of the difference between the squares of the first and second digital values; and means for accumulating the third digital value to measure electric energy.
Claim 4
Dependent Claim
92 words
An electronic type electric energy meter comprising: analog means for providing first and second analog signals indicative of the sum and difference, respectively, of a voltage input and a current input; A/D converter means coupled to the analog means for converting the first and second analog signals to first and second digital signals; means coupled to the A/D converter means for generating a third digital value indicative of the difference between the squares of the first and second digital values; and means for accumulating the third digital value to measure electric energy.
Claim 5
Dependent Claim
20 words
The electronic type electric energy of claim 2 wherein the analog means includes an analog adder and an analog subtracter.
Claim 6
Dependent Claim
20 words
The electronic type electric energy meter of claim 2 wherein the A/D converter means includes first and second A/D converters.
Claim 7
Dependent Claim
30 words
The electronic type electric energy meter of claim 3 wherein the A/D converter means includes first and second A/D converters respectively coupled to the analog adder and the analog subtracter.
References Cited (Backward Citations)
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JPS5275945A
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JPS55124845A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-21 | 1991-12-21 | 1992-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-21 | 1995-12-21 | 1996-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-21 | 1999-12-21 | 2000-06-21 | $7700.00 | Window Closed / Lapsed |