Abstract: An apparatus having a code strip carrier that is illuminated by an illumination system and a plurality of read heads is disclosed. Each code track includes a plurality of dark and light stripes. Each read head is positioned to detect light from a corresponding one of the code tracks as that code track moves relative to the read head, the read head generating a signal indicative of the intensity of light reaching that read head. One of the code tracks includes a first absolute position track that provides an indication of the absolute position value when the code strip carrier is at each of a plurality of predetermined absolute positions relative to the origin position. A different one of the code tracks includes an incremental position track for generating a digital value indicative of a displacement of the code strip carrier relative to the last predetermined absolute position.

Abstract: A rotational vibration testing device, including a rotating table, for testing both rotary shock and rotary vibration when used in conjunction with a pivoting shaker. The rotating table is mounted on a hub rotationally supported between two compression rings via tapered annular roller bearings preloaded in opposition. A motion arm connects to a radial arm on the side of the hub. The other end of the motion arm mounts to a height adjuster, which bolts to an electrodynamic shaker or other force generator. When the motion arm moves fore and aft, the linear acceleration is converted to rotational acceleration based on the radius from the stinger to the center of rotation. A nylon or equivalent median between the motion arm and the hub allows for sufficient flex without fore and aft play. The large tapered roller bearings preloaded in opposition eliminate z-axis acceleration and allow for greater payload testing.