| 摘要 |
PURPOSE:To obtain a sine wave over a wide range of frequency areas, by generating an analog voltage corresponding to a frequency by a microcomputer, and a D/A converter, and applying the analog voltage on a voltage controlled oscillator. CONSTITUTION:A microcomputer 1 outputs data regarding the frequency. The data is converted to the analog voltage by a D/A converter 3. The analog voltage V is inputted to a chopping wave generation circuit 4 in a voltage controlled oscillator VCO6, and a chopping wave having an oscillating frequency in proportion to the voltage V is generated. The chopping wave is converted to the sine wave by a sine converter 5. In this way, it is possible to obtain the sine wave over the wide range of the frequency areas without changing a circuit constant.
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