| 摘要 |
PURPOSE:To obtain an A/D converter which is capable of a higher accurated measurement in a short time, by providing a digital memory which produces an output signal when conversion exceeds the upper or lower limit of the converting range of an A/D converting part. CONSTITUTION:An analog signal supplied to an input terminal is converted into a digital signal through an A/D converting part 1. When an input is large, an over signal is delivered. Then the contents of a digital memory 3 are counted up. The value of the memory 3 is fed back to the minus side of a subtractor 6. Thus the input voltage of the part 1 is reduced. Then the contents of the memory 3 increase gradually up to a level within the range of measurement. Thus the count-up action is discontinued, and the value of the memory 3 is added 4 with the output of the part 1 to be delivered. At the same time, a looped double integration circuit and a subtractor are provided at an A/D converting part 5. As a result, a low-pass filter is not required. At the same time, no ripple error is caused although the part 1 carries out the conversion with any timing. |
