Adapting a scanning point of a sample and hold circuit of an optical smoke detector

Abstract

A smoke detector contains a radiation source for transmitting an illuminating radiation having a time sequence of radiation pulses, a radiation detector for receiving measurement radiation impinging on the radiation detector after at least partial scattering of the illuminating radiation, an amplifier circuit for amplifying an output signal of the radiation detector, an analog to digital converter having a sample and hold circuit for converting an analog output signal of the amplifier circuit into a digital measurement value, and a control device coupled to the radiation source and the sample and hold circuit. The control device is equipped for controlling the radiation source and the sample and hold circuit such that the time of a sampling point in time of the sample and hold circuit relative to a radiation pulse depends on the duration of the radiation pulse. A method for calibrating the described smoke detector is also revealed.

Dependencies are inferred from the claim text.