Patent ID: 7501861
Filing Date: 2009-03-10
Classification: H03D

Abstract:
1. A phase-difference detecting apparatus, for detecting phase difference between a first signal and a second signal, the first signal and the second signal having substantially the same frequency, the phase-difference detecting apparatus comprising: a signal generator, for generating a detection signal and delaying the detection signal by a fixed time in response to a control signal; a sample unit, for respectively sampling the detection signal according to the first signal and the second signal to generate a first sample value and a second sample value; and a comparer, for comparing the first sample value with a previous first sample value and comparing the second sample value with a previous second sample value, wherein when the first sample value is substantially equal to the previous first sample value and the second sample value is substantially equal to the previous second sample value, the comparer generates the control signal to drive the signal generator to delay the detection signal by the fixed time; wherein when the first sample value is not equal to the previous first sample value, the phase-difference detecting apparatus records a first time corresponding to difference between the present phase and an initial phase of the detection signal; wherein when the second sample value is not equal to the previous second sample value, the phase-difference detecting apparatus records a second time corresponding to difference between the present phase and the initial phase of the detection signal; wherein the phase-difference detecting apparatus obtains the phase difference between the first signal and the second signal according to the first time and the second time.