Abstract: A circuit for generating a time base signal from a power line signal produced by an alternating current (AC) power source. The circuit sets the output of a latch to a first state when a positive peak of the power line signal is detected, and sets the output of the latch to a second state when a negative peak is detected. Peaks are detected based upon comparisons between the power line signal and a reference voltage. A reference circuit derives the reference voltage from the power line signal using an AC-to-DC converter to generate a peak voltage signal from the power line signal and a reference generator to generate a reference voltage based upon the peak voltage signal. Positive and negative peaks are detected using positive and negative peak detectors.