Patent ID: 6424228
Filing Date: 2002-07-23
Classification: H03L,Y10S

Abstract:
A phase lock detection circuit, comprising:a phase detection circuit that produces a phase detect signal having one of a first logic state indicating phase agreement or a second logic state indicating phase disagreement responsive to a first input signal and a second input signal applied thereto, wherein said phase detection circuit is operative to transition said phase detect signal from said second logic state indicating phase disagreement to said first logic state indicating phase agreement upon a first logic transition of said first input signal occurring within a predetermined interval with respect to a first logic transition of said second input signal and to transition said phase detect signal from said first logic state indicating phase agreement back to said second logic state indicating phase disagreement upon a second logic transition of said first input signal failing to occur within the predetermined interval with respect to a second logic transition of said second input signal; and a stabilized phase lock indication circuit, electrically coupled to said phase detection circuit, that produces a phase lock indication signal having one of a first logic state or a second logic state, the phase lock indication signal changing to a respective one of its first and second logic states in response to the phase detect signal remaining in a respective one of its first and second logic states for a predetermined time interval that is at least as great as one cycle of the first input signal.