tokens: The following reviews shall be performed : 1 . System requirements review ( SRR ) NOTE This review results in the authorization to start the architectural design . The outputs reviewed and the items checked are detailed in clause 5.3.5 . 2 . Preliminary design review ( PDR ) NOTE PDR results in the authorization to start with the detailed design . The outputs reviewed and the items checked are detailed in clause 5.4.6 . 3 . Detailed design review ( DDR ) ( if applicable ) NOTE 1 DDR results in the authorization to proceed with the layout . The outputs reviewed and the items checked are detailed in clause 5.5.7 NOTE 2 In the case the design and layout is a concurrent or interdigitated activity ( for instance analog or FPGA design ) this review meeting can be combined with the subsequent CDR meeting . 4 . Critical design review ( CDR ) NOTE CDR results in the approval of design and layout and the release for prototype implementation . The outputs reviewed and the items checked are detailed in clause 5.6.7 . 5 . Qualification and acceptance review ( QR / AR ) NOTE QR / AR results in the final acceptance of the design and the release for FM production . The outputs reviewed and the items checked are detailed in clause 5.8.6 . 6 . Additional design reviews as agreed by the supplier .