摘 要：在許多SCART應用中，由于復雜的信號切換" title="信號切換">信號切換要求，通常采用專用IC實現SCART連接。這對于單SCART應用會帶來成本上的壓力。本文介紹的電路是一種可選方案，可以提供高質量" title="高質量">高質量的SCART接口而不需要額外的開關或復用" title="復用">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器" title="復用器">復用器。
?
??? 在歐洲，外部與電視機、機頂盒、錄像機(VCR)及其它視頻外設的連接都是通過SCART、Peritel連接器完成，EN50049對其引腳進行了詳細定義。根據SCART連接器的具體用途(TV SCART、AUX SCART或VCR SCART)，連接器可以作為輸入、輸出或同時作為輸入/輸出。
??? 另外，S-VHS要求將RED和CVBS引腳(第15腳和第20腳)與色度(C)和亮度(Y)信號引腳復用，使得這個接口更加復雜。
??? 絕大多數情況下，考慮到信號切換的復雜性，通常要求使用專用的SCART接口IC，但對于小規(guī)模、單向應用來說造成了很大的成本壓力。
??? 最簡單的結構是基于電視輸入和編碼器輸出的單SCART開關。以下電路提供了一種可選方案，能夠實現高質量的SCART連接，而且不需要額外的開關或復用器。
??? 圖中，MAX4384為四通道視頻運放" title="運放">運放，用于R/色度和CVBS/亮度格式的復用與緩沖。MAX4451雙通道視頻運放對BLUE和GREEN信號提供緩沖。圖1所示為輸出SCART，圖2為輸入SCART，圖3為雙向SCART。
?
?
圖1. 利用MAX4384和MAX4451構成輸出SCART
?
?
?
圖 2. 利用MAX4384和MAX4451構成輸入SCART
?
?
?
??? MAX4384和MAX4451電路設計為正向傳輸，配置為增益為2的同相放大器，采用等值的輸入和反饋電阻。電阻值不能過大，以免產生帶內極點；也不能過小，以免影響線性驅動。對于輸入或輸出SCART，色度/亮度使能信號經過反相后連接到RED/CVBS的使能端，通過單個引腳進行控制，分立電阻(Rdrive和Rterm)用作驅動和端接。圖3所示雙向SCART中，通過使能輸出SCART并將其輸入接地，使得RD/T經過運算放大器輸出端接地，從而利用輸出SCART驅動電阻(Rdrive)作為輸入SCART的端接(Rterm)。典型情況下，輸出SCART由DAC驅動，關閉DAC即可將所有輸入拉至地電位。
??? 由于專用的多輸入SCART開關不包含Y/CVBS和C/RED復用器，輸入或輸出SCART中的MAX4384可以配合這些開關實現擴展。
??? SCART接口的音頻部分可以采用MAX4493-MAX4495系列音頻放大器，可以構成立體聲架構或左、右聲道混音架構。