Circuit Design For Analysis And Measuring Instrument Of NMR System

NMR technology is widely used in industrial and agricultural production and daily life.For example, it can be used for the exploration of oil, natural gas, groundwater and othermaterial or nondestructive testing of food chemical industry. The paper mainly introducesthe basic working principle of NMR analysis measuring instrument. Then the paperintroduces the design of hardware circuit and software.The paper introduces design principle and method of instrument circuit in details, andprovides the measured waveform for some circuits. Hardware circuit consists of gauss metercircuit, emission circuit and receiving circuit. Gauss meter circuit consists of sensor circuit,data acquisition circuit and communication interface circuit. There is PC software to thegauss meter, and it can show magnetic induction intensity. Emission circuit mainly consistsof source circuit, time gate circuit, the first amplifying circuit, the last amplifying circuit,resonant circuit and discharge circuit. Frequency and amplitude adjustment is simple, and ithas enough excitation intensity to drive the NMR probe. Discharge circuit is simple andpractical, and it can quickly drain the residual energy with little interference. Receivingcircuit consists of the frequency selective circuit, amplifying circuit, high speed dataacquisition circuit and storage circuit. Receiving circuit with low noise and wide frequencyband can make a good collection and processing for NMR echo.Software design includes PC and MCU software. PC software written with VBlanguage includes gauss meter and DDS PC software. MCU software includes gauss meterprogram, DDS program and high speed data acquisition and storage program.The circuit and software of NMR system have been tested well. And the system hassome certain reference values for NMR system.