Optoelectronic detector for monitoring presence of objects in monitored region has outputs from rectifiers fed to summer which forms sum or difference based on clock phase shifts for near and far signals

摘要

The detector has a light pulse transmitter, and a receiver that outputs near signals and far signals, which are used to generate an object detection signal. The near signals and the far signals are fed to respective rectifiers (11,12), which are controlled by respective clock signals derived from the transmission clock of the light pulses. The rectified signals are fed to a summer (13) which forms the sum or difference based on the phase shift of the clock signals. The output from the summer is fed to an evaluation unit (9) which generates the object detection signal.