Phase measurement, traceability, and verification theory and practice

Methods are presented that allow high-resolution (better than +or-0.5 m degrees ) relative and absolute phase measurements between sine waves to be made at, or in the vicinity, of angles of 0 degrees , 60 degrees , 90 degrees , and 180 degrees . Three of these methods appear to be completely independent of each other. They involve the use of 180 degrees phase verification bridges, the use of a sine wave as a zero-degree intrinsic standard of phase, and the use of quadrature phase meters, respectively. A representative sampling of data comparing the different approaches is presented.<>