| 摘要 |
PURPOSE:To evade the continuous propagation of a main signal wherein a test pattern has an error by replacing and checking the test pattern which is inserted into free bits of the main signal and switching a main signal wherein the test pattern is not replaced and the main signal where the test pattern is replaced. CONSTITUTION:The main signal 101 is inputted to a 1st test pattern(TP) inserting circuit 1. A 1st TP102 which is outputted by a 1st TP generating circuit 2 is also inputted to the 1st TP inserting circuit 1 and inserted into the free bits of the main signal 101. The 2nd main signal 103 where the 1st TP102 is inserted is inputted to a TP check circuit 3 to check the TP. The decision result obtained by checking the TP is outputted as a switching control signal 106. The 1st TP102 inserted into the 1st main signal 103 replaces the 2nd TP104 and is outputted as a 3rd main signal 105. Then even if an error occurs to a TP between the 1st TP inserting circuit 1 and 2nd TP inserting circuit 4, the 2nd new TP104 is replaced to remove the error of the TP. |
