| 摘要 |
PURPOSE:To decide a proper input range by forecasting an analog value at sample time from an analog value sampled when an input range is decided. CONSTITUTION:Sample-and-hold circuits 41-44 controlled by a hold command signal hold sequentially an input analog signal ANAIN, a forecasting voltage is obtained by synthesizing the outputs at operational amplifiers 51, 52 into a prescribed value and the result is outputted at an A-D converter 32 as a digital signal via a switch 31. A contol section 40 decides the input range from the output and a gain designation code Gi is given to a programmable gain amplifier 30. The input analog signal ANAIN is amplified by the programmable gain amplifier 30. The input analog signal ANAIN is amplified by the programmable gain amplifier 30, inputted to the A-D converter 32 via the switch 31 and outputted to the post-stage. |
