Digital double-phase lock-in amplifier for laser online gas analyzer

A gas analyzer, lock-in amplifier technology, applied in the direction of amplifiers, parametric amplifiers, amplifier types, etc., can solve the problems of redundancy and complexity of pure analog phase-locked circuits, and achieve circuit redundancy and complexity, simple structure, and solution Effects on large storage and large computation problems

Inactive Publication Date: 2013-12-25
周健
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  • Abstract
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Problems solved by technology

[0004] The purpose of the present invention is to overcome the above problems in the prior art, to provide a digital dual-phase lock-in amplifier in a laser online gas analyzer, which solves the circuit redundancy and complexity of pure analog phase-locking, and also solves the problem of digital phase-locking. Problems of large storage and large calculations caused by number-related operations

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  • Digital double-phase lock-in amplifier for laser online gas analyzer
  • Digital double-phase lock-in amplifier for laser online gas analyzer
  • Digital double-phase lock-in amplifier for laser online gas analyzer

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Embodiment Construction

[0018] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0019] refer to figure 1 As shown, a digital dual-phase lock-in amplifier in a laser online gas analyzer includes an input signal 7, and the input signal 7 inputs signals to the first phase-sensitive detection 2 and the second phase-sensitive detection 11, and the first The phase-sensitive detection 2 and the second phase-sensitive detection 11 are connected to the reference signal 6, the first phase-sensitive detection 2 is connected to the first programmable gain amplifier 4 through the first low-pass filter 1, and the first programmable gain The input end of the amplifier 4 is connected to the X-bias input 3, and the X output 5 of the first programmable gain amplifier 4 is connected to the pin 63 of U2 of the ADC conversion module 8; the second phase-sensitive detection 11 passes through the second low-pass The filter 10 is conne...

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Abstract

The invention discloses a digital double-phase lock-in amplifier for a laser online gas analyzer. The digital double-phase lock-in amplifier comprises an input signal. The input signal inputs signals to phase sensitive detections which are connected with a reference signal. Each phase sensitive detection is connected with a programmable gain amplifier. An input end of each programmable gain amplifier is connected with a bias input. Outputs of programmable gain amplifiers are connected with an ADC (analog to digital converter) conversion module. The digital double-phase lock-in amplifier is simple in structure, and the problems that pure analog phase locking circuits are redundant and complex and digital related calculation of digital phase locking causes large storage and calculation are solved.

Description

technical field [0001] The invention relates to a lock-in amplifier, in particular to a digital dual-phase lock-in amplifier in a laser online gas analyzer. Background technique [0002] Since the DC component of the laser received by the photodetector is very strong, and the light intensity attenuation caused by molecular absorption is usually at – order of magnitude (at a wavelength of 1512 nm, an optical path of 1 m, and a linewidth of , the laser attenuation caused by 1 ppm ammonia gas at one atmospheric pressure is magnitude), so the lock-in amplifier needs to have AC amplification before phase detection and DC amplification after phase detection, and the minimum detection sensitivity is better than 50 uV. In addition, in order to facilitate the automatic phase adjustment of the software, a dual-phase output is required. [0003] The sensitivity and performance of the lock-in amplifier will affect the stability and repeatability of the laser frequency, and then ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03F7/00H03L7/00G01N21/01
Inventor 周健
Owner 周健
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