Although filter banks are designed to have the perfect reconstruction property, this property is not satisfied in some practical applications. In this case, filter banks behave as time-variant systems. As a result, the checkerboard effect is caused. In this paper, the condition for two channel filter banks with no checkerboard effect is shown, and for two channel FIR paraunitary QMF banks with real coefficients, a new design method to satisfy the condition is proposed. Our proposed method has a complete expression, and can be performed as unconstrained optimization.