| 摘要 |
PURPOSE: A circuit for detecting a loss of clocks in a transmission equipment is provided to detect a system clock trouble state using a clock extracted from line data when the system clock has a trouble. CONSTITUTION: A circuit for detecting a loss of clocks is comprised of the first frequency division circuit part(100), the second frequency division circuit part(200), a detection enable signal generation part(300), a detection cycle signal generation part(400), a system clock detection circuit part(500), and a DS(Digital Signal)3 clock detection circuit part(600). The first frequency division circuit part(100) lowers the speed of a clock in order to suitably detect a clock error in a system clock. The second frequency division circuit part(200) lowers the speed of a clock in order to suitably detect a clock error in a system clock and divides the clock. The detection enable signal generation part(300) generates a cycle signal to indicate error detection by a loss of clocks. The detection cycle signal generation part(400) generates a cycle signal to indicate the interval of loss in order to detect a loss of system clocks. The system clock detection circuit part(500) detects the error of a system clock using a DS3 detection enable signal generated by a DS3 clock. The DS3 clock detection circuit part(600) confirms the error of a system clock using a system clock signal. |
