Patent ID: 7308062
Filing Date: 2007-12-11
Classification: H04L

Abstract:
1. An apparatus for generating a system clock in synchronization with a network, comprising: a network synchronization reference signal generator receiving at least one reference signal from a communications network, selecting one of the received reference signal, frequency-dividing the selected reference signal, and outputting a reference signal for network synchronization; a network synchronization controller receiving the reference signal for network synchronization and a first clock pulse, and generating a first control voltage that allows the first clock pulse to be in synchronization with the reference signal for network synchronization; an ovenized voltage-controlled crystal oscillator (OVCXO) generating the first clock pulse whose phase and frequency are changed by application of the first control voltage; a system synchronization reference signal generator receiving the first clock pulse, frequency-dividing the first clock pulse, and generating different reference signals for system synchronization according to types of systems, the reference signal for system synchronization being used for synchronizing the system clock; a system synchronization controller receiving the reference signal for system synchronization and the system clock, and generating a second control voltage that allows the system clock to be in synchronization with the reference signal for system synchronization; a voltage-controlled oscillator (VCO) generating a second clock pulse whose phase and frequency are changed by application of the second control voltage; and a system clock generator receiving the second clock pulse, frequency-dividing the second clock pulse, and outputting the system clock.