Time measurement circuit and method, photoelectric distance meter, photoelectric distance measurement method

Abstract

Time measurement circuit and method, photoelectric distance meter, photoelectric distance measurement method. The time measurement circuit for the incoming signal has a comparator stage for generating a comparator output signal based on the incoming signal's fulfillment of a criterion, where exceeding or falling below a threshold is defined as the criterion. There is also provided a digitization stage for sampling the input signal fed to the digitization stage and converting it into digital data comprising sampled values ​​of the input signal, the sampling being performed at a defined sampling rate; and for determining the transmitted signal by evaluating the digital data. Evaluation unit for the time-sequential position of the incoming signal. A signal generation stage is connected between the comparator stage and the digitization stage, which is designed to generate and output a shape signal of known shape designed for post-sampling interpolation capability in a chronologically fixed manner according to the content of the comparator output signal. The evaluation unit then determines the time of the incoming signal while using chronological interpolation of the values ​​contained in the digital data and the known shape of the shape signal.

Description

technical field [0001] The present invention relates to a time measuring circuit and a photoelectric distance meter having such a time measuring circuit. Background technique [0002] Various principles and methods for determining a desired distance are known in the field of optical and / or optoelectronic distance measurement. One method is to emit pulses of electromagnetic radiation, such as a laser, towards an object to be measured, and then receive echoes from this object as backscattering objects, wherein the distance to the object to be measured can be determined based on the elapsed time of the pulses . Such pulsed time-of-flight testers (ToF, ie time-of-flight) are widespread as standard solutions in many fields. [0003] Two different schemes are used to detect return pulses. [0004] In the so-called threshold method, a light pulse is detected when the intensity of the radiation incident on the detector of the rangefinder used exceeds a certain threshold, where th...

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Problems solved by technology

At close range, the signal can saturate the receiver so that the shape of the transmitted signal is no longer correctly ascertained and the elapsed time is determined with insufficient accuracy

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