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| 摘要: |
| 数字式继电保护装置的模数转换系统多采用无源低通滤波＋多路模拟开关＋A／D转换器体系，在应用中发现当相邻两个通道的前一个通道输入量幅值远大于后一个通道时，后一个通道的转换结果相对误差很大，根据试验和理论分析，这种现象是由多路模拟开关输出引脚上的分布电容引起的，针对该问题，提出了一种电子开关将分布电容放电的方法，在成本增加不多的情况下可以将相对误差降低到可接受的水平以下。 |
| 关键词: 模数转换系统 通道 消除方法 数字式继电保护装置 A／D转换器 |
| DOI： |
| 分类号:TM774 |
| 基金项目: |
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| Cause of inter-channel influence in ADC system and its countermeasures |
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YIN Qiu-fan GUO Le
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| Abstract: |
| The structure of passive low-pass filter+MUX+A/D converter is widely used in ADC system of digital protective devices.When the value of a channel is far larger than that of the fol-lowing one,the relative error of the latter value becomes considerable.According to tests and theo-retical analysis,it is found that the distributing capacitors cause the inter-channel influence phenomenon.With a little cost augment ,an electronic switch is applied to discharge the dis-tributing capacitors,and the relative error reduces to an acceptable level. |
| Key words: ADC,inter-channel influence,digital protection, |
