Calibration test circuit for optical measurement instruments - has generator supplying phased signals and averaging circuit

摘要

A circuit for automatically testing the calibration of optical measurement instruments, esp. analysis instruments, measures the attenuation of light passing along a measurement path to a photoreceiver with an electronic evaluation circuit determining the reduction in the measurement signal. The automatic test procedure is simplified and its accuracy improved. The attenuation is a result of a defined reduction of the electrical parameter influencing the indication signal which is split up into pulses for the averaged reduction. An averaging stage connected in front of the indicator has a time constant greater than the pulse interval. The lamp voltage, modulator control voltage or photoreceiver output signal may be converted into pulsed form using a test signal generator.