| 摘要 |
PURPOSE:To release stop of the operation of a multivibrator by stopping signal supply to the line discrimination signal generating circuit after stopping the operation of the multivibrator in case of occurrence of the line discrimination signal. CONSTITUTION:If the phase relation between switching signal fH/2 having the half frequency of the horizontal frequency and transmission line information is not correct, a positive-polarity signal is generated from comparator 3. After its positive DC components are detected to supply the reset signal, which stops the operation, to multivibrator 1, signal supply to line discrimination signal generating circuit 2 is stopped to stop generation of the reset signal. Consequently, when the phase becomes correct, DC components of the output of comparator circuit 3 becomes zero, and multivibrator 1 starts the operation again, and thus, permanent stop of the operation does not occur. |
