Phase shifting circuits
First Claim
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1. In an electrical power measuring system, a phase shifting circuit comprising:
- a pair of input terminals to which is conducted an input signal having an amplitude and a frequency in a range of power supply frequencies;
a pair of output terminals from which is conducted an output signal having an amplitude;
a variable gain amplifying means and an active alternating current integrator connected in series between said input terminals and output terminals, said integrator exhibiting a substantially constant phase shift and a variable gain over said range; and
control means for controlling the gain of said amplifying means in dependence on the voltage between said input terminals and the voltage between said output terminals so as to maintain the amplitude of the voltage between said output terminals substantially equal to the amplitude of the voltage between said input terminals.
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Abstract
A phase shifting circuit includes: a pair of input terminals; a pair of output terminals; a variable gain amplifier and an active alternating current integrator, connected in series between the input terminals and the output terminals; and a control circuit for controlling the gain of the amplifier in dependence on the voltage between the input terminals and the voltage between the output terminals so as to maintain the amplitude of the voltage between the output terminals substantially equal to the amplitude of the voltage between the input terminals. The phase shifting circuit exhibits low variation of phase shift with input signal frequency.
25 Citations
8 Claims
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1. In an electrical power measuring system, a phase shifting circuit comprising:
- a pair of input terminals to which is conducted an input signal having an amplitude and a frequency in a range of power supply frequencies;
a pair of output terminals from which is conducted an output signal having an amplitude;
a variable gain amplifying means and an active alternating current integrator connected in series between said input terminals and output terminals, said integrator exhibiting a substantially constant phase shift and a variable gain over said range; and
control means for controlling the gain of said amplifying means in dependence on the voltage between said input terminals and the voltage between said output terminals so as to maintain the amplitude of the voltage between said output terminals substantially equal to the amplitude of the voltage between said input terminals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- a pair of input terminals to which is conducted an input signal having an amplitude and a frequency in a range of power supply frequencies;
Specification