| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an analog signal measuring method and a measurement circuit which enable expanding of a measuring range, without having to switch the range, even if the input signal goes out of the measuring range of an A/D converter. SOLUTION: A level comparison circuit 2, for outputting data in correspondence to an extent exceeding the measuring range, is connected to a differential amplifier 1 of which an input terminal is input by an analog input signal Si, and to a counter circuit 4, which performs up/down count, in correspondence to the output data. An analog voltage, in correspondence to the count result of the counter circuit 4, is generated by a D/A converter 5 and is input to another input terminal of the differential amplifier 1 and to an A/D converter 8 via an amplifier 3. Always values which do not exceed the level of the measuring range are input to the A/D converter 8.</p> |
