| 摘要 |
PURPOSE:To prevent a code error by means of the phase jump of an internal timing signal by detecting the time difference of a frame synchronizing pulse between a present output signal and input digital signals to be switched and controlling a signal switching timing. CONSTITUTION:A switching timing output circuit 1 detects the time difference of the frame synchronizing pulse between the present output signal and one of the input digital signals d1-dn which are to be switched. A switching timing signal is outputted from the circuit 1 excluding time delayed or advanced by (t) hours from the phase of the frame synchronizing pulse in the present output signal. When the signal and an external signal from a signal switching/setting circuit 4 are inputted, the signal is switched by a signal switching circuit 3 through a switching timing control circuit 2. Thus, the lack of a synchronous signal at the time of switching the signal can be prevented and a system does not become an asynchronous state. Thus, the code error by the phase jump of the internal timing signal can be prevented. |
