Circuit for detecting a clock error in a swept-beam system and related systems and methods

A method, comprising:

• activating a beam in response to a first portion of a clock that corresponds to a first predetermined location in a first line of a scan region as the beam moves in a direction, the clock having a phase;
• measuring a first intensity of the activated beam as the beam moves in the direction;
• activating the beam in response to a second portion of the clock that corresponds to a second predetermined location in a second line of the scan region as the beam moves in an opposite direction;
• measuring a second intensity of the activated beam as the beam moves in the opposite direction;
• weighting the first intensity by an amount that is related to the first location;
• weighting the second intensity by an amount that is related to the second location;
• and
• detecting an error in the phase of the clock from the weighted first and second intensities.