| 摘要 |
PURPOSE:To realize a floating-point A/D conversion function without a gain switch in the analogue stage, by selecting another A/D converter by discriminating whether an input is within a normal operation range of not. CONSTITUTION:A momentary level is detected by a level detector 6; an if it is within a normal operation range of an A/D converter 4, the output of the A/D con- verter 4 is selected by a digital signal synthesizer 7. If it exceeds the level range of the A/D converter 4, the output of an A/D converter 3 is selected by the digital signal synthesizer 7. The expontential part is set to zero if the output of the A/D converter 4 is selected, and a proper value of 0 or 1 is substituted in the lower bit of the mantissa, if the output of the A/D converter 3 is selected, thereby obtaining a floating point indication. |
