| 摘要 |
PURPOSE: An apparatus for switching a clock signal of a transmission system is provided to prevent errors in changing devices for supplying a clock by sharing signals at working and production part. CONSTITUTION: The system(60) includes a working clock providing unit(40) having a PLL controller(41), a voltage-controller oscillator(42), a signal generator(43) and a buffer(44), and a protection clock providing unit(50) having a PLL controller(51), a voltage-controlled oscillator(52), a signal generator(53), an inverter(54) and a buffer(55). The voltage-controlled oscillators of the working clock providing unit and the protection clock providing unit share an output. MFP, FP and system clock outputted from the buffer of the working clock providing unit to the system are returned to the signal generators of the working clock providing unit and the protection clock providing unit, to make one of the clock providing units be in tree-state when the other one is in active state.
|
