Tunable opto-acoustic gas analyzer includes several high frequency sources, modulators and lock-in amplifiers, enabling simultaneous detection and monitoring of several gases in e.g. anesthetic mixture

摘要

A turnable opto-acoustic filter comprises a modulation input optical radiation source and measurement section for the gas sample. The tunable opto-acoustic filter (6) includes a modulation input (19), optical radiation source (5) and measurement section (2) for the gas sample. The beam passes through the filter system and is diffracted to the detector (10). High frequency sources (12, 14, 16) are connected to the modulation input. Each has its own low frequency modulator (13, 15, 17). Lock-in amplifiers (20, 21, 22) are allocated to respective high frequency sources; all being connected to the detector output (11). These amplifiers deliver the transmission measurement signals.