of the present invention the identification and measurement of certain mathematical values the calculation of phase angles frame rates and the resultant accuracy to a large degree depend on a physical principle in mathematics called the beat frequency the following discussion explores the calculation of the phase angle according to a preferred embodiment of the method of the present invention the current composite sync signal single pixel can be represented by the function fs t k sin w 1 t y where f w 2pi or 17 ms 60 hz and y is the phase angle and let the image on the digital television video screen single pixel be represented by the function fi t p sin w 2 t q where f w 2pi could equal 60 hz 100 hz 120 hz etc and q is the phase angle and let the photo detector 8 of the invented optical gun 2 of the present invention observe the following the photo detector 8 of the invented gun 2 observes a beat frequency which is the composite of these two signals i e fi t and fs t the preferred embodiment of the method of the present invention is directed to find the values of w2 and q the instantaneous phase angle of these two functions as composed to p t is the solution the processor in the invented optical gun 2 does not attempt to solve the equation the invented optical gun 2 employs a table driven method whereby the magnitude p peak is collected across a period or a plurality of periods of one or a plurality of frames the highest point of this peak is the pointed position on the screen 20 of the gun 2 the table contains time offsets.