NEC NP2150, NP1150 user manual This allows you to manually adjust Clock and Phase

6. Using On-Screen Menu

[Image Options]

Adjusting Clock and Phase [Clock/Phase]

This allows you to manually adjust Clock and Phase.

....................Clock	Use this item to fine tune the computer image or to remove any vertical banding that might appear. This
	function adjusts the clock frequencies that eliminate the horizontal banding in the image.
	This adjustment may be necessary when you connect your computer for the first time.

Phase	Use this item to adjust the clock phase or to reduce video noise, dot interference or cross talk. (This is
	evident when part of your image appears to be shimmering.)
	Use [Phase] only after the [Clock] is complete.

81