Analog photoelectric measurement system measuring absolute values

摘要

The invention relates to an analog photoelectric measuring system measuring absolute values, particularly for small and hand measuring instruments, having the aim, above all, of increasing the noise immunity. The measuring system comprises an illuminating unit having an optical fibre connected to a light supply unit, and a strip-shaped receiver element which is connected with a centre connection to a voltage source and with its two end connections to a selective amplifier with LED output. Each LED output is followed by an optical fibre cable, the output ends of which are connected in each case to a photoelectric receiver amplifier, the outputs of which are connected to in each case one synchronous demodulator and an addition amplifier. The addition amplifier is connected to an LED drive amplifier for the light source and the latter is connected to a sine-wave oscillator.