Detection system and detection method of raster scanning spectrometer

Abstract

The invention relates to a detection system and detection method for a raster scanning type spectrograph. The detection control system is formed by connecting an upper computer with a speed measurement circuit through a microcontroller unit, a high-speed analog-digital converter unit, a phase-locked loop speed stabilizing unit and a chopper, and connecting the speed measurement circuit with the phase-locked loop speed stabilizing unit. Compared with an existing raster scanning type spectrograph, the raster scanning type spectrograph is free of reference signals and free of a phase shift circuit, a phase sensitive detection circuit and a filtering circuit. The DSP microcontroller unit and the phase-locked loop speed stabilizing unit are used for replacing the analog phase shift circuit, a synchronous integral circuit, a filtering phase inverter circuit and a reference signal shaping circuit. Digitization integration and filtering are achieved, a middle modulation link is eliminated, the circuit is simplified, and circuit system debugging difficulty is lowered. The detection system guarantees the frequency doubling relation of sampling control signals and detection signals through a phase-locked loop speed stabilizing circuit, synchronous sampling is achieved, no constant value requirement exists for detection signal frequency, the circuit is simple, debugging links are few, and equipment cost is lowered.

Description

technical field [0001] The invention relates to a digital lock-in amplifier used in a spectrum signal detection system, in particular to a signal detection system and a detection method of a raster scanning near-infrared spectrometer. Background technique [0002] As a commonly used analytical instrument, near-infrared spectroscopy has a wide range of applications. [0003] The near-infrared spectroscopy instrument consists of several parts such as a light source, a light cutter, a spectroscopic system, a sampler, a detector and a conversion circuit, a detection and control system, and a power supply. For the near-infrared spectroscopic instrument that adopts grating scanning for spectroscopic analysis, the composite light emitted by the light source will output monochromatic light of each wavelength through the monochromator, and will be mechanically modulated by the optical cutter into an AC amplitude modulated optical signal with a fixed frequency. The signal is sampled ...

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Problems solved by technology

[0007] CN102916665A discloses a "two-phase digital lock-in amplifier and its digital domain genlock algorithm", which realizes automatic tracking filtering and genlock functions, and can adapt to changing signal input frequencies, but also requires a phase difference of 90 ° square wave signal as reference signal

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