??? 摘? 要: 簡(jiǎn)要介紹了測(cè)量胎兒心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)" title="心電信號(hào)">心電信號(hào)的意義和方法,提出了一種綜合單片機(jī)和數(shù)字信號(hào)處理器(DSP)的數(shù)據(jù)處理系統(tǒng)的設(shè)計(jì)方案。文章從軟硬件兩部分詳細(xì)介紹了設(shè)計(jì)方案。結(jié)果顯示,本嵌入式心電信號(hào)處理系統(tǒng)能夠?qū)μ盒碾娦盘?hào)進(jìn)行實(shí)時(shí)高精度處理和監(jiān)控,而且具備便攜特點(diǎn),有很高應(yīng)用價(jià)值。?

??? 關(guān)鍵詞: 心電信號(hào);數(shù)字信號(hào)處理器;單片機(jī);自適應(yīng)濾波?

?

??? 隨著現(xiàn)代醫(yī)學(xué)技術(shù)的發(fā)展,通過(guò)測(cè)量胎兒早期的心電信號(hào)(ECG)可以對(duì)評(píng)估胎兒的健康狀況提供重要依據(jù)。實(shí)時(shí)方便地測(cè)量胎兒早期的心電信號(hào)具有重要的臨床意義。然而檢測(cè)胎兒的ECG非常困難,因?yàn)樗男盘?hào)幅度非常小,并且淹沒(méi)在母體自身的心電信號(hào)中。?

??? 目前提取胎兒心電最常用的是自適應(yīng)濾波方法。自適應(yīng)濾波器是一種能夠自己調(diào)整參數(shù)的特殊維納濾波器,設(shè)計(jì)時(shí)不需要預(yù)先知道輸入信號(hào)和噪聲的統(tǒng)計(jì)學(xué)特性,而是在工作過(guò)程中通過(guò)計(jì)算估計(jì)出所需的統(tǒng)計(jì)特性,并且以此為依據(jù)調(diào)節(jié)參數(shù),以達(dá)到最佳的濾波效果[1]。當(dāng)輸入信號(hào)的統(tǒng)計(jì)特性發(fā)生改變時(shí),它又能夠跟蹤這種變化自動(dòng)調(diào)整系數(shù),使濾波器的性能重新達(dá)到最佳。應(yīng)用中一般把母親腹部的信號(hào)作為主輸人,胸部信號(hào)作為參考噪聲輸入。由于母親自己心電信號(hào)x(n)與母親胎兒混合信號(hào)d(n)的提取時(shí)間不同,使得其在時(shí)域內(nèi)是非對(duì)應(yīng)關(guān)系。若直接將兩個(gè)信號(hào)相減,則得到的不是胎兒的信號(hào),但通過(guò)自適應(yīng)濾波器的自動(dòng)調(diào)整過(guò)程,將y(n)變成基于d(n)的對(duì)x(n)的估計(jì),使得新的混合信號(hào)在時(shí)域上與母親信號(hào)有了某種的對(duì)應(yīng)關(guān)系,從而直接將d(n)-y(n)得到胎兒信號(hào)。?

??? 除了提取胎兒的心電信號(hào)外,還需對(duì)處理后的胎兒心電信號(hào)進(jìn)行提取特征值等進(jìn)一步的處理與分析,一般為對(duì)心電波的平滑和各個(gè)特征點(diǎn)的檢測(cè)。雖然使用基于神經(jīng)網(wǎng)絡(luò)算法及其他的基于統(tǒng)計(jì)學(xué)原理的方法能得到精確的測(cè)量結(jié)果,但是由于其軟件算法的復(fù)雜度較高,會(huì)帶來(lái)實(shí)時(shí)性差、能耗高等一系列問(wèn)題。通用的設(shè)計(jì)方法是用差分闕值法檢測(cè)特征值,闕值的選取是先驗(yàn)的,并且提取的信息實(shí)際上不是特征點(diǎn)的信息,而是由特征點(diǎn)所確定的各個(gè)時(shí)期的波形信息,如心率的確定是通過(guò)兩個(gè)相鄰周期內(nèi)R點(diǎn)的間隔時(shí)間確定的。?

??? 為了實(shí)現(xiàn)上述功能,本文設(shè)計(jì)了嵌入式的心電信號(hào)處理系統(tǒng),完成對(duì)信號(hào)的濾波、分析處理過(guò)程,以滿足心電數(shù)據(jù)處理的高速度、高實(shí)時(shí)性要求,并且能夠做到對(duì)胎兒信號(hào)實(shí)時(shí)監(jiān)測(cè)。?

1 系統(tǒng)硬件設(shè)計(jì)?

1.1 系統(tǒng)性能與選型?

??? (1)DSP?

??? 自適應(yīng)濾波器要求的計(jì)算量比較高,并且由于要求實(shí)時(shí)測(cè)量,所以運(yùn)算數(shù)據(jù)量極大,對(duì)處理器的要求很高,一般的單片機(jī)很難滿足要求,因此需要高性能的DSP芯片來(lái)實(shí)現(xiàn)。如果抽頭為51 200,階數(shù)L=5,每次抽頭采取5個(gè)乘加運(yùn)算(MAC),則一共要采樣51 200×5=256 000個(gè);若用200Hz采樣率,采樣間隔為1/200=5ms,以所選取的TI公司的TMS320VC5402為例,進(jìn)行一次MAC為10ns,則一次濾波運(yùn)算的數(shù)據(jù)運(yùn)算時(shí)間是256 000×10=2.5ms,由此可以看到C54完全可以滿足系統(tǒng)實(shí)時(shí)性的要求。?

??? TI公司的定點(diǎn)數(shù)字信號(hào)處理器TMS320VC5402含有專門(mén)的功耗控制功能,具有很低的靜態(tài)功耗;改進(jìn)的哈佛結(jié)構(gòu),多總線(1條程序總線,3條數(shù)據(jù)總線和4條地址總線)和6級(jí)流水線,有40位的算術(shù)邏輯運(yùn)算單元(ALU),包括2個(gè)獨(dú)立的40位累加器和1個(gè)40位的桶形移位寄存器,指令周期為10ns,運(yùn)算速度為100MIPS,并且具有強(qiáng)大的尋址能力,1M×16bit的最大尋址外部空間,內(nèi)置16K×16bit RAM,4K×16bit ROM,其乘法單元和加法單元可以在一個(gè)流水線狀態(tài)周期內(nèi)完成一次MAC運(yùn)算,數(shù)據(jù)處理能力強(qiáng),支持JTAG硬件仿真^[3]。?

??? (2)MCU?

?? 從信號(hào)特征上來(lái)說(shuō),心電信號(hào)時(shí)域特征(波形的輪廓)明顯,幅度比較微弱(mV級(jí)),正常人心臟每分鐘跳動(dòng)65～75 次左右,也就是說(shuō),它的頻率不到1Hz。但對(duì)于一些心臟病人來(lái)說(shuō),其諧波分量(QRS波群)頻率可能達(dá)到100Hz,這就表明采樣頻率不會(huì)過(guò)高,一般在200Hz左右^[2]。?

??? 心電信號(hào)的處理對(duì)于精度沒(méi)有很高的要求,一般8位左右的A/D就可以滿足系統(tǒng)需要,出于簡(jiǎn)化電路考慮,實(shí)際選用較多的是MCU片上A/D。綜上所述,本文選用了TI公司的MSP430F169,其含有一個(gè)片內(nèi)的12位A/D,還有一個(gè)12位D/A,能夠方便地將處理后的數(shù)據(jù)轉(zhuǎn)化為模擬信號(hào)。?

??? MSP430系列單片機(jī)是TI公司推出的一種超低功耗的混合信號(hào)控制器,具有16位的RISC結(jié)構(gòu),極高的代碼運(yùn)行效率,豐富的外設(shè)資源,并且支持JTAG和FLASH在線編程^[4]。?

??? ①極低功耗。給單片機(jī)供電的電壓可低到2.5V;工作電流低,在3V供電、1MHz情況下僅消耗電流0.4mA;該系列具有5 種節(jié)能模式, 在閑置模式下的電流值是0.1LA。?

??? ②運(yùn)算能力強(qiáng)。MSP430F169基于16位RISC結(jié)構(gòu),內(nèi)部帶有硬件乘法器,可以執(zhí)行16×16 位的帶符號(hào)數(shù)或不帶符號(hào)數(shù)乘法運(yùn)算。?

??? ③片內(nèi)資源豐富。在MSP430F169內(nèi)部集成了A/D、LCD驅(qū)動(dòng)電路、16位定時(shí)器、看門(mén)狗和串行口(UART)以及專用的可編程I/O口等,片內(nèi)集成2KB的RAM和60KB的ROM。?

??? (3)存儲(chǔ)器?

??? 為了增強(qiáng)系統(tǒng)的擴(kuò)展性和提高DSP的處理能力,系統(tǒng)增加了外置的FLASH和SRAM。C54x系列DSP只能同異步的存儲(chǔ)器直接相接,并且TMS320VC5402的指令周期為10ns。為保證DSP無(wú)等待運(yùn)行,需要外部存儲(chǔ)器的速度10ns左右,考慮現(xiàn)有芯片的性價(jià)比做如下選擇:?

??? FLASH:AM29LV400-55,256K×16bit/512×8bit,指令周期55ns,電源電壓3.3V(加入5個(gè)軟件等待); ?

??? SRAM: CY7C1021V33-12,64K×16bit,指令周期12ns,電源電壓3.3V(加入1個(gè)等待)。?

??? (4)電源?

??? 良好穩(wěn)定的電源是電路正常工作的保證,對(duì)于DSP這樣的高端處理器,還需要滿足其對(duì)內(nèi)核和IO不同的上電順序,這里特別選用了TI公司專門(mén)為DSP設(shè)計(jì)的電源芯片TPS73HD318,5V輸入1.8/3.3V混合輸出,并且配備了專門(mén)的復(fù)位芯片。?

1.2 系統(tǒng)架構(gòu)?

??? 本系統(tǒng)構(gòu)建以TI公司的MSP430F169為核心,TMS320VC5402為運(yùn)算單元,系統(tǒng)硬件框圖如圖1所示。?

?

?

??? 系統(tǒng)中MSP430F169作為MCU,控制整個(gè)電路的工作,DSP負(fù)責(zé)邏輯運(yùn)算。為了能夠更加有效地發(fā)揮DSP的運(yùn)算能力,分別采用了FLASH和SRAM芯片擴(kuò)展DSP的數(shù)據(jù)空間和存儲(chǔ)空間,并且用CPLD對(duì)存儲(chǔ)空間的映射進(jìn)行控制,以達(dá)到對(duì)映射地址動(dòng)態(tài)控制的目的。?

1.3 通信模塊設(shè)計(jì)?

??? 系統(tǒng)設(shè)計(jì)的核心是MSP430和TMS320VC5402連接通信問(wèn)題,本文采用主機(jī)接口(HPI)通信模式。HPI是一個(gè)8位的并行口,MSP430可以方便地通過(guò)這個(gè)接口訪問(wèn)DSP整個(gè)數(shù)據(jù)空間,直接由DSP的硬件流水進(jìn)行優(yōu)化,沒(méi)有多余的開(kāi)銷。連接方式如圖2所示。?

?

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??? HPI有兩種工作模式:?

??? (1)共用訪問(wèn)模式(SAM)。此狀態(tài)下MSP430和DSP都可以訪問(wèn)HPI存儲(chǔ)器,如果二者的讀取周期發(fā)生了沖突,主機(jī)(MSP430)有優(yōu)先權(quán)。?

??? (2)僅主機(jī)訪問(wèn)模式(HOM)。在此模式下只有主機(jī)(MSP430)可以訪問(wèn)HPI存儲(chǔ)器,DSP處于復(fù)位狀態(tài)或最小功耗狀態(tài)。?

??? 其中8位數(shù)據(jù)總線(HD0～HD7)負(fù)責(zé)與主機(jī)交換信息,因?yàn)門(mén)MS320VC5402接口為16位,所以主機(jī)與DSP之間數(shù)據(jù)傳輸由2個(gè)連續(xù)的字節(jié)組成。由HBIL引腳指示正在傳輸?shù)氖歉?位還是低8位。主機(jī)通過(guò)HCNTL0和HCNTL1指定所訪問(wèn)的寄存器是控制寄存器HPIC、地址寄存器HPIA還是數(shù)據(jù)寄存器HPID。HPIA寄存器還可以被設(shè)置為自動(dòng)增尋址方式,以提高對(duì)連續(xù)地址訪問(wèn)操作的效率。HCS是片選信號(hào),在主機(jī)訪問(wèn)HPI時(shí)必須保持為低。HAS是地址選通信號(hào),一般用作地址鎖存或不用(接高電平)。HR/W為讀寫(xiě)選通信號(hào),用來(lái)確定數(shù)據(jù)傳輸?shù)姆较颉?IMG src="http://files.chinaaet.com/old/uploadfiles/jishu/jslw/2009022603005193.gif" border=0>和是數(shù)據(jù)選通信號(hào),用于在主機(jī)訪問(wèn)周期控制數(shù)據(jù)的傳輸。當(dāng)沒(méi)有使用信號(hào),并且HCS信號(hào)處于低電平時(shí),或可用于對(duì)HBIL、HCNTL0/1和HR/W信號(hào)的采樣。因?yàn)镠DS1和HDS2內(nèi)部互斥,所以不能同時(shí)將和置低。硬件連接示意圖如圖3所示。?

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1.4 外置存儲(chǔ)器設(shè)計(jì)?

??? 為了增強(qiáng)系統(tǒng)的擴(kuò)展性及擴(kuò)展DSP存儲(chǔ)空間,特增加了外置FLASH和SRAM,并由CPLD控制二者與DSP之間的時(shí)序關(guān)系。圖4為外接存儲(chǔ)器系統(tǒng)的硬件框圖。?

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??? CPLD配備了JTAG接口,便于程序燒錄和日后修改。由于CPLD的時(shí)序嚴(yán)格,并且速度快、易編程,非常適于用作接口邏輯控制芯片。本設(shè)計(jì)采用了Alreta公司的EPM7032S芯片,利用DSP的MSTRB和R/W控制SRAM和FLASH的OE與WE的選通,A15、DS和XF控制FLASH的選通,PS和A19控制SRAM的選通。?

????? VHDL語(yǔ)言描述如下:?

????? OE<=‘0’when (mstrb=‘0’and rw=‘1’) else‘1’;?

????? WE<=‘0’when (mstrb=‘0’and rw=‘0’) else‘1’;?

????? CE(sram)<=‘0’ when(ps=‘0’and A19=‘0’) else ‘1’;?

????? CE(flash)<=‘0’ when(ps=‘0’and xf=‘0’ and a19=?‘1’) or (ds=‘0 and xf=‘1 and a19=‘0’) else‘1’;?

????? 為了減少每次開(kāi)機(jī)時(shí)的工作量,將處理程序(自適應(yīng)LMS算法)燒入了FLASH中,并在系統(tǒng)復(fù)位時(shí)由編寫(xiě)的Bootloader自動(dòng)將外部FLASH中的程序?qū)懭隓SP內(nèi)部的DRAM中,采用了在線燒制的方式。具體實(shí)現(xiàn)方式不再給出。編寫(xiě)時(shí)要注意復(fù)位時(shí)內(nèi)部RAM的映射問(wèn)題,因?yàn)閺?fù)位時(shí)DSP自動(dòng)將OVLY置1^[3],將內(nèi)部的RAM映射到所有數(shù)據(jù)空間的每一頁(yè)的0080～3fff中,所以實(shí)際編寫(xiě)B(tài)ootloader時(shí)程序?qū)懭霐?shù)據(jù)空間的起始地址應(yīng)當(dāng)為4000。?

??? 復(fù)位后FLASH映射到數(shù)據(jù)空間的0000～ffff,SRAM映射到程序空間的0000～ffff上,待燒錄完成后,由通用IO引腳XF控制映射到程序空間的80000～bffff。數(shù)據(jù)空間由內(nèi)部和外部RAM獨(dú)占。?

2 系統(tǒng)軟件設(shè)計(jì)?

??? 單片機(jī)與DSP軟件通信流程如圖5所示。由于本系統(tǒng)中的位已置1,所以實(shí)際通過(guò)軟件控制位置1和置0來(lái)完成每個(gè)讀寫(xiě)周期。DSP的工作流程與其正好相反,一旦接受到MSP430傳來(lái)的中斷信號(hào),便馬上進(jìn)入中斷子程序,從發(fā)送來(lái)的地址中取出數(shù)據(jù)進(jìn)行運(yùn)算處理,完成后對(duì)其取反后存在相同的地址內(nèi),之后置位HINT中斷單片機(jī),退出中斷子程序。

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??? 系統(tǒng)總軟件流程由圖6所示。MSP430采集完數(shù)據(jù)后,進(jìn)入HPI發(fā)送子程序,發(fā)送完數(shù)據(jù)后進(jìn)入低功耗模式等待DSP的處理結(jié)果,并將其顯示出來(lái);DSP上電后進(jìn)入低功耗狀態(tài),待MSP430將數(shù)據(jù)傳遞完后啟動(dòng)濾波算法對(duì)數(shù)據(jù)進(jìn)行處理,待處理結(jié)束后將結(jié)果傳回到MSP430中,重新進(jìn)入低功耗狀態(tài)等待下一次中斷。?

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3 結(jié)果分析?

??? 圖7為對(duì)實(shí)際采集的母嬰混合心電信號(hào)和母親自身信號(hào)進(jìn)行分析處理后的實(shí)時(shí)數(shù)據(jù),通過(guò)Matlab儀表控制工具箱中的Serial類函數(shù)及其相關(guān)函數(shù),讀取串口發(fā)送的數(shù)據(jù),并繪制得到。該類函數(shù)操作雖然效率一般并且對(duì)中斷的響應(yīng)比較差,但是對(duì)于本文所用的串口數(shù)據(jù)的讀取處理,有著操作簡(jiǎn)單、直觀的優(yōu)點(diǎn)。具體過(guò)程如下:?

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??? (1)創(chuàng)建串行口設(shè)備對(duì)象Serial();?

??? (2)設(shè)置波特率=9 600,幀格式(停止位=0,數(shù)據(jù)位=8,校驗(yàn)位=0等);?

??? (3)設(shè)置具體函數(shù),完成與硬件系統(tǒng)的連接和之間的數(shù)據(jù)交換;?

??? (4)設(shè)置關(guān)閉和刪除設(shè)備對(duì)象函數(shù)。?

??? 設(shè)置過(guò)程比較簡(jiǎn)單,不再給出詳細(xì)的程序,具體設(shè)置方法見(jiàn)參考文獻(xiàn)6。?

??? 通過(guò)對(duì)輸入和輸出心電波形比較可以看到,輸出波形失真度低,特征點(diǎn)對(duì)應(yīng)準(zhǔn)確。結(jié)果表明系統(tǒng)可以滿足設(shè)計(jì)要求,轉(zhuǎn)換精度高,實(shí)時(shí)性很好。?

??? 本文通過(guò)對(duì)胎兒及母嬰心電混合信號(hào)特點(diǎn)的討論,給出了一整套的嵌入式數(shù)據(jù)處理解決方案,不但滿足了信號(hào)處理的大運(yùn)算量、高實(shí)時(shí)性的要求,還具備了便攜特點(diǎn),有很高的實(shí)用價(jià)值。?

參考文獻(xiàn)?

[1] 姚天任.現(xiàn)代數(shù)字信號(hào)處理.武漢:華中科技大學(xué)出版社,2002.?

[2] 王保華.生物醫(yī)學(xué)測(cè)量與儀器.上海:復(fù)旦大學(xué)出版社,2002.?

[3] Texas Instruments Incorporated.TMS320C43x系列DSP的CPU與外設(shè).北京:清華大學(xué)出版社,2006.?

[4] 沈建華,楊艷琴,翟曉曙.MSP430系列16位超低功耗單片機(jī)原理與應(yīng)用.北京:清華大學(xué)出版社,2004.?

[5] 狄國(guó)偉,唐曉英,劉偉峰.電信心號(hào)采集模擬系統(tǒng)的研制.中國(guó)儀器儀表學(xué)會(huì)醫(yī)療儀器分會(huì)2006年學(xué)術(shù)年會(huì)暨中國(guó)儀器儀表學(xué)會(huì)醫(yī)療儀器分會(huì)第三屆第三次理事會(huì)論文匯編[C],2006.?