Abstract: A method and apparatus for measuring the wall thickness of transparent objects, such as glass tubes, is presented wherein a narrow band (beam) of light is projected onto a surface of the object at an angle other than 90.degree.; and the beams reflected by the adjacent boundary surface of the object and that boundary surface thereof which is spaced behind that adjacent boundary surface by the distance to be measured are focused onto the image plane of a receiver. A movable deflecting element is provided in the optical path between the light source and the image plane of the receiver. The lines of intersection between the band of light and the boundary surfaces of the layer to be measured (the lines of intersection being represented by bands of light on the image plane of the receiver), are then moved or urged by the deflecting element in the direction in which they are spaced apart.

Abstract: An optical micrometer and position detector has a rotating mirror driven by a motor which deflects a coherent light beam toward a collimating lens for directing parallel light beams at an object to be measured. A photoelectric detector determines portions of the parallel beams which are blocked by the object and provides a pulse signal from which a dimension or position gap signal is generated and displayed. The rotating mirror is mounted on a shaft for corotation with a cylindrical encoder for generation of electric signals proportional to the angular velocity of the mirror and which controls a voltage controlled oscillator having an output which is combined with the dimension or position gap signal for display. The displayed signal is thus automatically corrected for minimization of external and/or internal mechanical influences on the angular velocity of the mirror.

Abstract: An apparatus is provided for producing a trigger signal in accordance with the occurrence of an event, for example the end of the last pulse of a train of pulses, which occurs in an almost periodic manner within periodically consecutive time intervals and having a specific distinguishing feature relative to the remainder of the events occurring within each of said time intervals. The apparatus comprises a signal examination and time measurement circuit (3) which receives a signal on a rail (2) which represents the events and which determines the occurrence time of the event having the distinguishing feature. The output of the circuit (3) is provided to a holding circuit (6) which is controlled by a clock signal and which has its output connected to a signal modification circuit (8) which modifies the output signal of the circuit (6) so that it represents a slightly earlier time.