Method and apparatus for measuring horizontal sync subcarrier phase.

摘要

The 50% point of the leading edge of sync is used to acquire the value of a color burst locked CW carrier, and a quadrature color burst locked CW carrier. The acquired value of each of the two carriers are split into two values representing the value on alternating horizontal lines. This requires the generation of a one-half horizontal rate signal (H/2) which can have an arbitrary phase relationship. The H/2 phase is associated with each of the four acquired CW carrier values and that information is used by a computing device. The H/2 signal is also used to gate a 30 Hz vertical frame pulse to generate a 15 HzV1 color frame pulse. The computing device receives the color frame pulse and records the time the pulse occurs. This information represents the minimum and sufficient set of data to obtain a complete measure of sync to subcarrier phase (SC/H) and color frame comparison. By multiplexing the acquisition electronics between two video sources, SC/H and color frame comparisons can be made by the computing device.