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模数转换是自动检测仪表中的一个重要环节。过去模数转换器的改进大都集中在电子线路上,线路越来越复杂,元件也增多,稳定性和可靠性便降低,成本增加。微处理机问世后,很快被应用在仪表改善性能方面。将模数转换器和微处理机相结合,利用其数据处理和自校正功能,使模数转换在精度、转换速度、稳定性等方面都有了很大提高。反映生产过程各个参数的传感器输出电信号常是很小的,因而对干扰信号特别对工频干扰信号的抑制则成为保证测量精度的关键之一。本文讨论了如何用微型计算机提高模数转换器的抗工频干扰能力的问题,讨论了数字滤波和电源同步等方法;重点分析了一般双积分式模数转换器随着电网频率波动而抗工频干扰能力大大下降的问题,并提出了一种可以解决这一问题的由微处理机控制的双积分式模数转换器。文中介绍了这种模数转换器的电路结构和程序设计。用在微型机自动检测系统中,只占用了微型机的很小一部分工作量,从经济上和技术上取得较好的统一。我们还通过现场工业实验说明这个设计是可行的。
A / D conversion is an important part of automatic instrumentation. In the past, most of the improvements in analog-to-digital converters were focused on electronic circuits. As the circuits became more and more complicated, the number of components increased, the stability and reliability were reduced, and the cost was increased. After the advent of microprocessors, it was quickly applied to improve the performance of the instrument. The combination of analog-digital converter and microprocessor, the use of its data processing and self-correction function, the A / D conversion has been greatly improved in accuracy, conversion speed, stability and so on. The sensor output electrical signal that reflects each parameter of the production process is often very small, so it is one of the keys to ensure the measurement accuracy that the interference signal, especially the interference of the industrial frequency interference signal, is suppressed. This article discusses how to use microcomputers to improve the anti-jamming capability of analog-to-digital converters, and discusses methods such as digital filtering and power synchronization. The analysis of typical double-integrated analog-to- Frequency interference ability greatly decreased, and proposed a solution to this problem by the microprocessor-controlled dual-integrated analog-digital converter. This article describes the circuit structure and program design of this analog-to-digital converter. Used in the automatic detection system of the miniature machine, it occupies only a very small part of the workload of the miniature machine, and achieves a better economic and technical unification. We also demonstrate that this design is viable field lab experiments.