Abstract: A pair of orthogonally polarized optical beams that differ in frequency by a constant oscillator-generated reference frequency are directed through and traverse respective fixed and variable length paths of a heterodyne interferometer, following which the beams are mixed and directed to a detector that generates an electrical measurement signal having a phase that varies with changes in the variable path length. Changes in the measurement signal phase are determined by counting cycle-to-cycle phase changes of the reference frequency signal between sampling instants defined by time-spaced occurrences of a known phase of the measurement signal. The resulting count is simultaneously used to determine both changes in length of the variable length path and the elapsed time interval between the sampling instants.

Abstract: The disclosure relates to a television titling apparatus which is substantially the same as a conventional television titling apparatus designed for left-to-right character presentation, but includes a novel subsystem and method which can be utilized to effect display of characters from right-to-left for languages which so require. Reverse image stroke representations are stored in a stroke generator. An auxiliary storage is provided for storing a scanline of stroke bits from the stroke generator. Scanlines of stroke bits are read out of the auxiliary storage in reverse order from the order in which they were read in; i.e., on a last-in-first-out basis. Preferably, the auxiliary storage includes first and second stores which are alternately operable to read in and read out successive scanlines of stroke bits so that one scanline of stroke bits is being read out while the next scanline of stroke bits is being read in.