Given a model about the signal between electromagnetic flowmeters' poles, which contains useful signal and several disturb signals, two of the main disturb signals are mainly talked about, which is differential interference and in-phase interference. The voltage between the electrodes multiplies with excitation voltage and the signal U0 is gotten. There are two parts consist of U0: DC signal and AC signals. This DC signal is useful signal, which is linear relationship with pipe flow velocity signal, so it is the signal that we want. Through this way the interferent signals are separated from original signals, and practical circuit proves that this method is effective.%电磁流量计极间信号不仅包含流量信号,而且掺杂有各项干扰信号.流量信号和干扰信号都是由相对独立的信号源产生,所以它们之间以物理叠加的关系构成了电磁流量计极间信号.因此将上述信号构建数学模型,经解析:直流分量代表管内水流速度信号,即流量信号.交流分量呈现为干扰信号特征.采用信号分离手段,较容易得到流量信号并去除干扰信号.实验数据表明通过建模分析可以有效地去除电磁流量计极间干扰信号,此方法设计的电磁流量计误差范围比传统的正弦波励磁电磁流量计误差范围小±0.05％.
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