| 摘要 |
PURPOSE:To eliminate the need for external setting and to simplify the operation by providing a self-check function whose frequency division output is a non-code word if a fault takes place in the input or the circuit and raising the circuit automatically from the initial state to the state of a code word. CONSTITUTION:If a permanent fault takes place in the circuit, non-code words '0', '0' or '11' are included in outputs X, X'. Thus, the fault of the circuit is checked by monitoring the outputs X, X'. When the frequency division outputs X, X' in the initial state are non-code words '0', '0' the frequency division output X of the 1st FF 7 is inverted from logic '0' to logic '1' at the leading of the input signal CK. Thus, the frequency division outputs X, X' are set to code words '1', '0'. In case of non-code words '1', '1' the frequency division output X is inverted from logic '1' to logic '0' at the trailing of an input signal CK'. Thus, the frequency division outputs X, X' are set to the code words '0', '1'. Thus, the circuit rises automatically and it is not required to be set externally. |
