| 摘要 |
PURPOSE:To prevent a phase synchronizing circuit from detecting a synchronizing signal erroneously by using an auxiliary window signal whose window is narrowered more than a reference window signal during the detection of the synchronizing signal so as to sample input information. CONSTITUTION:An output of a phase detector 1 is connected to a voltage controlled oscillator 3 via an LPF 2. The output of the oscillator 3 is inputted to a reference counter 6 and becomes a reference window signal (c). The signal (c) and the output of an auxiliary counter 5 are inputted to an auxiliary signal circuit 4 to generate auxiliary window signals (e,f). A data discrimination circuit 7 discriminates whether or not the input information (a) is consecutively in the signals (e,f). When the information does not exist in the signals (e,g), a reset signal (g) is outputted. A synchronizing signal detection circuit 8 changes a synchoronization detection signal (i) if the state is consecutive that the specified number of the information (a) and the signal (g) are not inputted. |
