摘要：設(shè)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(xiàn)心電信號實時在線采集。設(shè)計系統(tǒng)是由硬件部分和虛擬儀器VI兩部分構(gòu)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(shù)據(jù)采集卡" title="數(shù)據(jù)采集卡">數(shù)據(jù)采集卡和計算機5個部分；虛擬儀器VI的前面板對應(yīng)著一臺實際儀器的面板，實現(xiàn)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(xiàn)數(shù)據(jù)采集卡對信號的模／數(shù)轉(zhuǎn)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?qū)崿F(xiàn)心電信號的動態(tài)實時顯示。
關(guān)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(lǐng)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(chǎn)技術(shù)要求較高，設(shè)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(xiàn)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(shè)計靈活。
    本設(shè)計系統(tǒng)采用的是編程軟件系統(tǒng)LabVIEW 8．2和數(shù)據(jù)采集卡PCI6251，構(gòu)建了心電數(shù)據(jù)的實時采集系統(tǒng)。

1 心電信號采集系統(tǒng)的實現(xiàn)
    設(shè)計系統(tǒng)是由硬件部分和虛擬儀器VI兩部分構(gòu)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(shù)教學和實驗室套件)、數(shù)據(jù)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(shù)據(jù)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(yīng)的程序框圖。前面板對應(yīng)著一臺實際儀器的面板，實現(xiàn)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(xiàn)數(shù)據(jù)采集卡對信號的模／數(shù)轉(zhuǎn)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(shè)計
    軟件前面板對應(yīng)的是一臺實際儀器的面板，實現(xiàn)的是對儀表的控制和信號表達功能，設(shè)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(shè)置顯示2 s，可以顯示一個完整的心動周期；縱坐標對應(yīng)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(xiàn)數(shù)據(jù)采集卡對信號的模／數(shù)轉(zhuǎn)換，信號的處理顯示。
    LabVIEW是通過利用數(shù)據(jù)采集助手(DAQmx)節(jié)點來控制DAQmx設(shè)備完成數(shù)據(jù)采集的，拖出DAQ Assist子模板，并完成設(shè)備和通道的選擇，以及相關(guān)屬性設(shè)定。然后在DAQAssistant對應(yīng)的引腳上添加了掃描率、采樣數(shù)、停止按鈕、以及一次采樣的周期。
    DAQ Assistant的數(shù)據(jù)輸出引腳data連接心電實時顯示模塊，這樣就可以把經(jīng)數(shù)據(jù)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(shè)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(xiàn)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(shè)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(nèi)插在PC機的數(shù)據(jù)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(shù)據(jù)采集的軟件部分，要設(shè)定前面板掃描率為250 Hz，采樣數(shù)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(wù)，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(wù)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(wù)，采集到的波形如圖5所示。

3 結(jié)論
    基于LabVIEW的心電信號采集系統(tǒng)，除了能實現(xiàn)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(shè)計靈活。采用LabVIEW編程軟件和數(shù)據(jù)采集卡PCI6251，構(gòu)建了心電數(shù)據(jù)的實時采集系統(tǒng)，實現(xiàn)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。