Erwin Sick Gmbh Optik-Elektronik

Frank Blohbaum

The invention relates to a method for determining the light transit time along a measurement path arranged between a measuring apparatus and a reflecting object, wherein a light transmitter contained in the measuring apparatus sends a modulated light signal s(t) along the measurement path, which is received by a light receiver contained in the measuring apparatus, is converted into a received signal e(t), and is evaluated in the measuring apparatus, wherein the light signal s(t) to be transmitted is stored in the form of digital values in a transmitter memory; wherein the stored digital values are sequentially read out and supplied to a digital/analog converter acted on by a clock signal and controlling the light transmitter; wherein the received signal e(t) is supplied to an analog/digital converter acted on with the identical clock signal; wherein the values delivered by the analog/digital converter are deposited in a receiver memory; wherein a correlation function k(t) is formed between the signals s(t) and e(t) stored in the transmitter memory and in the receiver memory; and wherein the maximum K.sub.max =k(t.sub.max) of the correlation function k(t) is found, with t.sub.max corresponding to the transit time to be determined, and also to an apparatus for carrying out this method.

Method and apparatus for determining the light transit time over a

The invention relates to an optical scanning apparatus for the identification of a code (11) consisting of sequential light and dark fields which respectively form modules (16, 17, 18, 19, 20, 21, 22) put together from an upwardly restricted integral multiple number of base running lengths (B1), to a module width (M), with a predetermined number of sequential modules (16, 17, 18, 19, 20) and base running lengths (B1) in the code forming a mark (25). The optical scanning apparatus guides a light bead (13), the extent of which is less than the base running length (B1) and at most only fractionally larger than the base running length (B1) of the code (11), over the modules (16, 17, 18, 19, 20, 21, 22) in sequence. By means of its light receiver (15), the light scattered back from the regions of the code (11) met by the light bead (13) is received, and a corresponding electrical signal is transmitted at the output (24). A sequence of individual pulses is formed by differentiation and rectification. A differential stage (26) with rectification and a counting stage (27) for the clock pulses generated by a clock generator (28) between two predetermined heights of the flanks of sequential individual pulses is connected to the light receiver (15). The individual counting results are applied to a memory (29) and stored there.

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Bad Krozingen, Germany

Frank Blohbaum