摘要：設計了一套基于LabVIEW的心電" title="心電">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號" title="心電信號">心電信號采集系統(tǒng)" title="采集系統(tǒng)">采集系統(tǒng)，實現心電信號實時在線采集。設計系統(tǒng)是由硬件部分和虛擬儀器VI兩部分構成。硬件部分包括電極、心電圖機" title="心電圖機">心電圖機、NI ELVIS、數據采集卡" title="數據采集卡">數據采集卡和計算機5個部分；虛擬儀器VI的前面板對應著一臺實際儀器的面板，實現的是對儀表的控制和信號表達功能；程序框圖是程序的圖形化源代碼，實現數據采集卡對信號的模／數轉換，信號的分析顯示。實驗室測試表明，基于Lab-VIEW的心電信號采集系統(tǒng)能夠實現心電信號的動態(tài)實時顯示。
關鍵詞：LabVIEW軟件；PCI6251；虛擬儀器VI；心電采集

    心電信號是人體生物電活動信息的表征，通過心電信號可以判斷人體的健康狀況。心電研究一直是醫(yī)學領域的一個重要課題，心電圖是心血管等疾病臨床檢查診斷的重要方法。心電信號主要頻率范圍為0．05～100 Hz，幅度約為0～4 mV，信號十分微弱。
    傳統(tǒng)的心電記錄方法主要靠心電圖機來完成，其信號采集、處理和顯示主要由硬件電路完成，電路生產技術要求較高，設備價格較貴，且維護和更新不便。
    基于LabVIEW的心電信號采集系統(tǒng)，除了能實現傳統(tǒng)心電圖機的采集功能外，還可通過編程可使用高效且功能強大的軟件來自定義采集、分析、存儲、共享和顯示功能等；儀器面板布置簡捷，設計靈活。
    本設計系統(tǒng)采用的是編程軟件系統(tǒng)LabVIEW 8．2和數據采集卡PCI6251，構建了心電數據的實時采集系統(tǒng)。

1 心電信號采集系統(tǒng)的實現
    設計系統(tǒng)是由硬件部分和虛擬儀器VI兩部分構成。系統(tǒng)方框圖如圖1所示。

1．1 心電信號采集系統(tǒng)的硬件部分
    心電信號的硬件部分包括5個部分：電極、心電圖機、NIELVIS(虛擬儀器技術教學和實驗室套件)、數據采集卡和計算機。在使用標準的導聯(lián)方式下，心電圖機采集人體心電信號，并進行一系列的預處理，包括放大信號和濾除干擾，然后把信號送入數據采集卡，以供計算機的下一步處理。

1．2 心電信號采集系統(tǒng)的虛擬儀器VI
    虛擬儀器VI包括前面板和與之相對應的程序框圖。前面板對應著一臺實際儀器的面板，實現的是對儀表的控制和信號表達功能；程序框圖是程序的圖形化源代碼，實現數據采集卡對信號的模／數轉換，信號的處理顯示等。其具體的程序流程圖如圖2所示。

1．2．1 心電信號采集系統(tǒng)VI的前面板設計
    軟件前面板對應的是一臺實際儀器的面板，實現的是對儀表的控制和信號表達功能，設計包含了波形顯示、采樣時間、掃描率和停止按鈕等。心電信號采集系統(tǒng)VI的前面板如圖3所示。

    心電實時顯示圖用來動態(tài)地顯示采集的心電信號的變化情況。其橫坐標為時間，設置顯示2 s，可以顯示一個完整的心動周期；縱坐標對應的是幅值，單位為毫伏。
1．2．2 心電信號采集系統(tǒng)VI的程序框圖
    程序框圖是程序的圖形化源代碼，可以實現數據采集卡對信號的模／數轉換，信號的處理顯示。
    LabVIEW是通過利用數據采集助手(DAQmx)節(jié)點來控制DAQmx設備完成數據采集的，拖出DAQ Assist子模板，并完成設備和通道的選擇，以及相關屬性設定。然后在DAQAssistant對應的引腳上添加了掃描率、采樣數、停止按鈕、以及一次采樣的周期。
    DAQ Assistant的數據輸出引腳data連接心電實時顯示模塊，這樣就可以把經數據采集板卡PCI6251處理的心電信號在心電實時顯示波形圖中顯示出心電信號波形。
    添加while循環(huán)框，把整個設計的模塊框住，使得心電信號的采集在完成一次采集周期后再繼續(xù)下一次采樣周期，以實現連續(xù)心電信號采集的目的，達到動態(tài)、實時顯示心電信號的效果。心電信號采集系統(tǒng)VI的程序框圖如圖4所示。

2 心電信號采集系統(tǒng)的測試
    按圖1連接實驗設備。心電圖機的標準導聯(lián)有4個電極，分別為紅、黃、綠、黑，把它們分別接到右手、左手、左腳和右腳的各個腕部。心電圖機的CRO接口分別接到NI ELVIS面板的模擬信號輸入端的ACHO+端和ACHO-端。NI ELVIS輸出與內插在PC機的數據采集卡相連。
    選擇心電圖機的各種按鍵，打開心電圖機和NI EIVIS。在數據采集的軟件部分，要設定前面板掃描率為250 Hz，采樣數為500。右擊心電實時顯示波形圖的屬性，將橫坐標改為0～2 s，以使采集的波形多于一個周期；縱坐標為幅值，單位毫伏。檢查無誤后，點擊運行，可以看到在心電實時顯示波形圖中有不斷變化的心電信號，這就是基于LabVIEW的心電信號采集系統(tǒng)在進行連續(xù)的采集任務，并在心電實時顯示波形圖中動態(tài)地顯示出來了。同時前面板的采集時間也實時地顯示了一個周期的采集任務進行的時間。為方便看到采集的波形圖，點擊前面板的停止按鈕，系統(tǒng)暫停采集任務，采集到的波形如圖5所示。

3 結論
    基于LabVIEW的心電信號采集系統(tǒng)，除了能實現傳統(tǒng)心電圖機的采集功能外，還可通過編程可使用高效且功能強大的軟件來自定義采集、分析、存儲、共享和顯示功能等；儀器面板布置簡捷，設計靈活。采用LabVIEW編程軟件和數據采集卡PCI6251，構建了心電數據的實時采集系統(tǒng)，實現心電信號的動態(tài)實時顯示。其中在程序框圖VI上增加心率計算模塊，完成R波的提取和心率顯示，有待進一步地研究。