Non dispersive Infra-red (NDIR) acquisition system for a measurement sensor circuit, amplifies modulated direct current signals to reduce noise from the infra-red sensor

摘要

The non dispersive infra-red (NDIR) system (10) includes an infra-red (IR) sensor (12) with a modulator (21) for chopping the direct current signal of the sensor into components with a first specific frequency of approxiametly 1kHz. An amplifier (24) connected to the modulator amplifies the signals which are demodulated (26) and sychronized to the original modulator signal. A filter (28) receives the demodulated signals and filters out frequencies above 3 kHz to obtain the required signals.