INPUT REFERENCE CLOCK SELECTING APPARATUS FOR SYNCHRONIZATION

摘要

The apparatus extracts clock signal from a trunk line or receives clock signal through an exclusive clock line to generate internal clock signal. The apparatus includes a clock selecting unit (1) for selecting one clock amont input clock signals, a passive controller (6) having a selection switch to select one input reference clock, a clock signal inspector (5) for checking the normal input of input reference clocks and a programmable array logic unit (4) connected to a processor to transmit selection signal to the clock selecting unit (1) when the selection mode is manual, and otherwise to select to clock signal by the passive control unit (6).