 +_____________________________________________________________________
 ] AUTHOR:            ]     RECONFIGURATION         ] DR:              ]
 ] MELISSA NOLIN      ]       PROGRAM NOTE          ]  107023          ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:            ]
 ] DP3/X34775         ]      RELEASE NOTE( )        ]MARCH 27,1992     ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI21/STS-46 RC1, STS-46 FL1   ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ] MAJOR SOFTWARE AREA:    PASS(X) BFS( )] OPS MODES AFFECTED:         ]
 ] SSME**( ) DEU**( ) T&G( ) DFL/FPL**( )]                             ]
 ] TFL**( ) TCS**( ) I-LOAD( ) LEVEL C(X)] S2                          ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: PDI RECONSTRUCTED DATA STREAM                    ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS:  COMMAND AND DATA ANNEX; STS-46                ]
 ]_____________________________________________________________________]
 ] TITLE:  STS-46 EOIM PDI FRAME LOCK PROBLEM                          ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]FOR STS-46, FRAME LOCK MAY NOT OCCUR FOR EOIM (EVALUATION OF OXYGEN  ]
 ]INTERATCTION WITH MATERIALS) RECONSTRUCTED DFL (DECOM FORMAT LOAD)   ]
 ]FORMATS 2,29, AND 30.  THE PRIMARY FORMAT FOR EOIM HAS 40 WORDS CON- ]
 ]TAINED IN 25 MINOR FRAMES.  IF A PAYLOAD CONTINGENCY SITUATION       ]
 ]ARISES, THEN A NEW TFL (TELEMETRY FORMAT LOAD) WILL BE LOADED WHICH  ]
 ]CONTAINS RECONSTRUCTED DFL FORMATS FOR EOIM DOWNLINK.  THE RECON-    ]
 ]STRUCTED FORMAT FOR THE INPUT EOIM DATA HAS 200 WORDS IN 5 MINOR     ]
 ]FRAMES.  WITHIN THE 200 WORDS, THE MINOR FRAME SYNC PATTERN OCCURS 5 ]
 ]TIMES PER MINOR FRAME.  THE MAJOR FRAME SYNC CODE ONLY OCCURS ONCE IN]
 ]WORD 5 OF THE MINOR FRAME.  THE PDI (PAYLOAD DATA INTERLEAVER) WILL  ]
 ]LOOK FOR THE MAJOR FRAME SYNC CODE (00) AFTER IT HAS ACQUIRED MINOR  ]
 ]FRAME SYNC (WORD LOCK).  DUE TO THE RECONSTRUCTED FORMAT, THE PDI MAY]
 ]BEGIN READING AT ANY POINT IN A MINOR FRAME, THUS THE PDI COULD      ]
 ]ACQUIRE MINOR FRAME LOCK FROM THE WRONG MINOR FRAME SYNC PATTERN.  IF]
 ]THIS IS THE CASE, THE PDI WILL NEVER ACQUIRE FRAME LOCK (MAJOR FRAME ]
 ]SYNC).                                                               ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]IF THE RECONSTRUCTED DFL FORMATS FOR EOIM (FORMATS 2,29, AND 30) ARE ]
 ]LOADED VIA A TFL LOAD DURING STS-46, THE CREW AND GROUND MUST WATCH  ]
 ]FOR EOIM FRAME LOCK TO OCCUR.  IF FRAME LOCK DOES NOT OCCUR, THEN THE]
 ]CREW OR GROUND SHOULD DESELECT AND RESELECT THE PDI INPUT SOURCE FOR ]
 ]EOIM UNTIL FRAME LOCK IS OBTAINED.                                   ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]RSOC:   SILVIA WERRE      DATE 04/29/92]                             ]
 ]     -------------------      ---------]                             ]
 ]MOD:JEFFERSON D. POWELL   DATE 04/29/92]                             ]
 ]    --------------------      ---------] DARRELL E. STAMPER 05/01/92 ]
 ]SW MGR:   C. L. STOUGH    DATE 04/29/92]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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