| 摘要 |
PURPOSE:To attain the A/D conversion having high resolution by using generally a commercially available A/D converter, by separating an inputted analog signal into an accurate and a coarse signal and converting and synthesizing respectively the separated signals. CONSTITUTION:The inputted analog signal 1 is weighted for accuracy/coarseness by an operational amplifier 2 via a precision type resistor 3. The accurate analog signal 5 and the coarse analog signal 8 weighted by the amplifier 2 are sent to A/D converters 4, 7, where the signals are converted into an accurate n-bit digital signal 6 and a coarse m-bit digital signal 9, and they are sent to an erasable P-ROM10 and synthesized. The low-order q bits of the accurate signal are thrown away in this case, then the resolution of an A/D converter 12 is (n+m-1-q) bits, if the overlapped bit number between the coarse and the accurate bits is assumed as P bits. The limit of the resolution as the A/D converter is expressed as n+1<=M<=n+m-1(n>=2). |
