| 摘要 |
PURPOSE:To detect an error of a selection circuit by selecting a signal of a fixed amount of value corresponding to the parity signal of an input selecting signal and then comparing the parity signal with the signal of said fixed value. CONSTITUTION:When a binary selection is applied to a decoder 100, a data group selection gate 140 selects one-data group signal line out of those signal lines 131-138 and delivers it onto an output data group signal line 150. While a correct parity selection gate 240 selects a correct parity signal set previously at 1 or 0 and delivers it to a correct parity signal line 250. The delivered parity signal is compared with a parity signal which is given via a parity signalline 210 by a comparator 200. The result of comparison is usually coincident and correct. However, the result of comparison is not coincident if a decoder 100 or gate signal lines 121-128 have some error. Thus a selection error of a selection circuit is detected. |
