24-Bit ∑-Δ Programmable A/D Converter AD7731 and Its Application in a Temperature Measuring System

摘要

In the measuring and controlling field, the precision of measuring relates the conversion precision from the analog-to-digital signals (ADC) in a large degree. The performance of A/D conversion circuit has a crucial influence to the measuring precision. So in this paper we introduced a high precision programmable A/D converter -AD7731. At the same time we detailedly described the interfacing method and the correlative program about the AD7731 with the 8-bit Microcontroller-Unit 89C51, and we also apply it in a high precision temperature measuring system, due to apply AD7731 converter, the resolution arrive at 0.001°C, the system error less than 0.055 percent.