a timing alignment or offset display shows the relationship between a reference signal and a test signal , in particular two analog or digital video signals . timing extraction circuits derive a lower frequency signal synchronized to horizontal lines and a higher frequency signal synchronized to the pixel sampling rate . a reference time pulse is also derived from the reference signal . two offsets are counted by determining a line count and a sample or clock cycle count between corresponding reference points in the test and reference signals . a coarse line count offset and a fine timing offset are thereby obtained and are displayed by movable markers on opposite sides of a scale line . the markers are centering and aligned when the frame / field alignment and the color and / or sample portions of the signals correspond in time . tabular data , distinct coloring and alarms also are depicted .