Digitizing power meter
First Claim
1. A digitizing power meter for measuring voltage root mean square, average power, and power factor of an analog signal, comprising:
- a first circuit system for converting the voltage component of an input analog signal into a first digital signal, said first circuit system including a voltage amplifier (1), a voltage sampling/holding circuit (3), and a voltage A/D converter (4);
a second circuit system for converting the current component of the input analog signal into a second digital signal, said second circuit system including an ampere amplifier (8), a current sampling/holding circuit (10), and a current A/D converter 11;
a signal detector means (5) connected to said voltage amplifier and to said ampere amplifier for producing a square wave signal;
a phase lock circuit (6) connected to said signal detector means for changing the frequency of the square wave signal;
a trigger circuit (7) having its input connected to the output of the phase lock circuit for developing a timing signal;
said trigger circuit having separate outputs connected to said voltage sampling/holding circuit, said current sampling/holding circuit, said voltage A/D converter, and said current A/D converter for delivering timing signals thereto;
a digital signal processing circuit comprising a microprocessor (18) and a RAM (17), anda photo isolator (19) having a first side thereof connected to said digital signal processing circuit, and a second side thereof connected to said trigger circuit and to said A/D converters.
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Accused Products
Abstract
A digitizing power meter for measuring voltage and current'"'"'s root-mean-square, average power and power factor, which includes a voltage detector circuit and a current detector circuit to measure voltage and current analog signal; a phase-lock circuit, a voltage Sampling/Holding circuit, a current Sampling/Holding circuit, a trigger circuit, a voltage A/D converter and a current A/D converter to convert analog signal to measure to digital signal; and a digital processing circuit to accurately measure out voltage and current'"'"'s root-mean-square, average power and power factor by means of the operation of its microprocessor.
63 Citations
2 Claims
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1. A digitizing power meter for measuring voltage root mean square, average power, and power factor of an analog signal, comprising:
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a first circuit system for converting the voltage component of an input analog signal into a first digital signal, said first circuit system including a voltage amplifier (1), a voltage sampling/holding circuit (3), and a voltage A/D converter (4); a second circuit system for converting the current component of the input analog signal into a second digital signal, said second circuit system including an ampere amplifier (8), a current sampling/holding circuit (10), and a current A/D converter 11; a signal detector means (5) connected to said voltage amplifier and to said ampere amplifier for producing a square wave signal; a phase lock circuit (6) connected to said signal detector means for changing the frequency of the square wave signal; a trigger circuit (7) having its input connected to the output of the phase lock circuit for developing a timing signal;
said trigger circuit having separate outputs connected to said voltage sampling/holding circuit, said current sampling/holding circuit, said voltage A/D converter, and said current A/D converter for delivering timing signals thereto;a digital signal processing circuit comprising a microprocessor (18) and a RAM (17), and a photo isolator (19) having a first side thereof connected to said digital signal processing circuit, and a second side thereof connected to said trigger circuit and to said A/D converters. - View Dependent Claims (2)
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Specification