Detection of absorption lines in absorption spectroscopy, used for gas sensor, involves processing detector signals for differentiating to give high resolution of low depth absorption with high accuracy

摘要

Detection of absorption lines in absorption spectroscopy, for gas sensors, involves deriving a detector ground signal from a ramp detector signal, to give an output signal with a low stroke movement in its level from the difference between the two signals. Alternatively, the detector signal can be smoothed for differentiating. Preferred Features: The detector signal passes through an ohmic resistance (24) and the capacitor (25) of a deep pass filter (26) for smoothing, so that the output signal can be differentiated at the following differentiator (27). The differentiator has an input amplifier (28) which attempts to charge the capacity from the voltage difference for compensation at the input. The charging current in the capacity flows through an ohmic resistance (30), where the current drop is registered by a difference amplifier (31) formed by an operation amplifier (32).