All-digital nonlinear detection device and method

Abstract

The invention discloses an all-digital nonlinear detection device, which comprises a signal excitation system, a transceiving conversion system, a signal receiving system and a digital control and signal processing system, and is characterized in that a DDS (Direct Digital Synthesizer) and a numerical control high-voltage signal amplification technology are combined, so that fine adjustment of excitation signals is realized, the adjustment stride is less than 0.05 dB, and the excitation amplitude as large as possible is realized; in combination with a numerical control high-voltage power amplifier, a high-voltage low-pass filter, a high-voltage high-pass filter and the like, single-probe nonlinear ultrasonic detection is realized, and sub-harmonics, secondary harmonics and higher harmonics in echoes are measured; a numerical control low-noise signal amplifier is adopted to fully amplify a received signal to be close to the full amplitude of the ADC module, so that a higher signal-to-noise ratio is realized; and the digital lock-in amplifier is adopted, so that the analysis of any bandwidth signal at a specific frequency point can be realized.

Description

technical field [0001] The invention belongs to the field of detection equipment, in particular to an all-digital non-linear detection device and method. Background technique [0002] In industries such as petroleum, chemical industry, energy and metallurgy, there are a large number of pipelines transporting high-temperature, high-pressure, flammable, explosive, and radioactive liquids. The large-diameter pipeline in the main circuit of a nuclear power plant is one of the key equipment of the entire nuclear power plant. to the safe operation of the entire nuclear power plant. Nuclear power plants include a variety of large-diameter pipes, most of which are connected by welding, and are subjected to high temperature, high pressure, and radioactive water environments during the operation of nuclear power plants. Working in this environment for a long time will cause stress corrosion cracks, corrosion, collision, thinning and other conditions. Conventional ultrasound detect...

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Problems solved by technology

However, this method mainly solves the problem of insufficient bandwidth of the amplifier of the receiving signal, and does not solve the problem of excessively large amplitude adjustment steps of the excitation signal, excessive distortion of the transceiver conversion part, and failure to simultaneously cover subharmonics in the existing nonlinear ultrasonic testing system. and the range of higher harmonics, the inability to flexibly adjust the measurement bandwidth of the frequency point to be measured, etc., so it is necessary to invent an all-digital control non-linear ultrasonic single-probe detection system

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