Abstract: The existing mainstream testability allocation methods are all one-time allocation, without feedback and modification. Once the unit allocation index is too high to achieve, the system index cannot be achieved. Therefore, a testability allocation method based on quadratic allocation is proposed. First, an improved fault rate allocation method based on arctangent function is proposed to implement the primary allocation. Second, the preliminary design of testability and testability prediction are successively implemented to determine whether the secondary allocation is required. If it's required, an amending function based on the relative difficulty coefficient is proposed to implement the secondary allocation and obtain the final allocation result. Finally, the effectiveness and advancement of the quadratic allocation method are verified by simulation calculation and practical application.

Key words: testability allocation, quadratic allocation, fault detection rate, allocation function, relative difficulty coefficient