中文摘要：

测试性设计的关键是要寻求一种良好的测试性模型。混合诊断模型是一种将功能模型和故障模式模型建立在一个系统模型中测试性设计与分析模型，它通过对测试的定义，有效地描述了测试、故障模式和功能三者之间的关系。并且，该模型已经在DSI公司的eXpress软件中得到实现。最后，应用放大器实例，在express软件中进行混合诊断建模．通过诊断学习，得到诊断策略和测试性设计的指标，验证了模型的有效性。事实证明，混合诊断模型是一种有效的测试性模型。

英文摘要：

The key of design for testability （DFT） is a good testability model. Hybrid diagnostic model （HDM） is a model which makes function and failure mode model into one system model. By defining the test, it effectively describes the relationship between test, failure mode and function, and it has already been realized in eXpress software. Finally, by adopting an＇ amplifier model and making the hybrid diagnostic modeling in eXpress software, the diagnostic strategy and index of DFT were obtained through diagnostic study and this model was proved effective. HDM is an effective testability model.