| 摘要 |
PROBLEM TO BE SOLVED: To omit a DC cut capacitor without using the resistance potential dividing of a power source and a liner amplification circuit. SOLUTION: A control circuit 1 modulating pulse width, switching circuits 2-1, 2-2 and 3 controlled by the same period by an offset pulse system with the control circuit exist. The switching circuits 2-1 and 2-2 have the same characteristics. A low pass filter 4 making the output of the switching circuit 2-1 into an analog signal, a low pass filter 6 making the output of the switching circuit 2-2 into the analog signal and a low pass filter 5 making the output of the switching circuit 3 into the analog signal are installed. A load 20 is connected between the output terminal 7 of the low pass filter 4 and the output terminal 8 of the low pas filter 5 and a load 21 is connected between the output terminal 9 of the low pass filter 6 and the output terminal 8 of the low pass filter 5. Thus, DC levels between the power output terminals 7 and 8 and the power output terminals 8 and 9 can always be set to almost zero.
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