| 摘要 |
<p>PURPOSE:To indicate the minute change in supply voltage correctly and clearly by subjecting the supply voltage to A/D conversion and later to digital expansion for indication. CONSTITUTION:The supply voltage is divided by resistances R1 and R2 and is converted to a digital value by an analog-digital converter 1. The supply voltage converted to the digital value is inputted to a digital expansion circuit 21. Based on the analog-digital converted value inputted, the digital expansion circuit 2 selects the pulse of a cycle changing in a double system, thereby converting the arithmetical change of the digital value to the geometrical change of the cycle and performing the digital expansion. The output of the digital expansion circuit 2 drives a sound- producing body SS. According to the sound-producing cycle of the sound-producing body SS, the change in the supply voltage is indicated.</p> |
