| 摘要 |
A line frequency detector (100) receives an input signal (102) representing a power source and detects a line frequency of the power source based on the input signal. The line frequency detector includes a first band pass filter (112A) having a pass band centered at an upper end of an expected frequency range of the power source and a second band pass filter (112B) having a pass band centered at a lower end of the expected frequency range. The input signal is filtered by the first and second band pass filters, generating a first characteristic signal and a second characteristic signal (122A, 122B). The line frequency detector determines a characteristic ratio (126) between the first characteristic signal and the second characteristic signal, and maps the characteristic ratio to the line frequency (130) of the power source. |
