Device for distance measurement using semiconductor laser in the visible wavelength region by propagation time method

摘要

A device for distance measurement using a semiconductor laser in the visible wavelength range, which functions according to the echo time method, includes a collimation objective for bundling the transmitted measuring beam bundle, a circuit arrangement for modulating the measuring beam, a receiving objective for receiving and imaging the measuring beam bundle reflected at the distant object onto a receiving device, and an evaluation device for determining and displaying the distance measured to the object. The circuit arrangement for modulating the measuring beam and the evaluation device can be switched between two different operating modes. In the first operating mode, the modulation takes place using a first frequency and in the second operating mode using a second frequency. These frequencies stand in a whole-member ratio to each other. The reflected signal in the first operating mode is multiplied using a third frequency and in the second operating mode using a fourth frequency, before they are sampled for evaluation, in the first operating mode using a first sampling frequency and in the second operating mode using a second sampling frequency. In this context, the first sampling frequency is the difference between the fourth and the second frequency, and the second sampling frequency is a whole-number fraction of the second frequency.