| 摘要 |
PURPOSE:To protect code detection with a small amount of hardware by using an RAM to protect code detection with signals of individual channels multiplexed as they are. CONSTITUTION:The output of a code detecting circuit 102 is written in a RAM 103, and read data on output signal line 115 and 116 have phases controlled by a phase control circuit 106 and are put onto input signal lines 112 and 113. The output of an all '1' detecting circuit 107 and the output of an all '0' detecting circuit 108 are inputted to a selector 109, and if '1' is selected when output signals of both detecting circuits are '1' and '0', this state indicates code detection and is outputted to a code detection protecting output terminal 110. If '0' is selected when said output signals are '0' are '1', this state indicates that code detection is not performed or detection is released. If said output sginals are '0' together, the signal on an output signal line 118 is selected. Thus, the RAM103 is used to protect code detection with signals of individual channels multiplexed as they are. |
