The Study On Signal Conditioning Technology In Tokomak

The current mainstream fusion research device tokamak is a kind of complex electromagnetic device system. When the discharge experiments of the tokamak were in operation, there are extremely complex electromagnetic environment around there, and there is a large amount of signals around the device. There is a large number of experiments signal need to transmit to the data acquisition system for acquisition and storage. During transmission a large number of experimental signal vulnerable to environmental disturbance, also cannot completely meet the requirements of data acquisition system. So the study of signal conditioning technology is of grate use, the anti-jamming processing, isolation, enlarging is an indispensable link for data acquisition system, it is of very important significance to guarantee the accuracy of the experimental signal acquisition and to ensure reliable operation plant. In this paper, on the basis of the demand of J-TEXT data acquisition system to signal transmission, studied the signal optical transmission system and the signal isolation technique, designed and developed of the corresponding signal conditioning circuit system for practical application.In order to solve the problems of veracity and reliability of the trigger signal for the systems which are in different physical location or far away from the central control system, basing on the optical signal transmission technology, this article introduced the design and reconstruct of the digital fiber optic transmission system for J-TEXT, completed the modular of optical transmitted circuit and light receiving circuit, the circuit system realize the signal transmission delay is less than 100 ns, and the system can provide load with more than 400 m A drive current. The system was actually used in motors speed control system and other subsystems, the effect of the system for signal conditioning is obvious, stable performance and good reliability.In order to achieve the signal transmission in the specific system under the complex electromagnetic environment, this paper studies the digital signal isolation technology and analog signal isolation technology. Designed the digital signal isolation modular system which was used for the short signal transmission system, the circuit can achieve 600 k Hz signal transmission without distortion, and drive the relay load well. The paper designed 50 k Hz bandwidth capacitance coupling analog isolation circuit, matching the NI DAQ card, which was widely used in the low bandwidth required subsystem in good condition. Designed the 2.7 MHz bandwidth optical coupling analog isolation circuit, the availability of the presented isolation amplifier was verified in the Langmuir probe floating potential measurement system on J-TEXT.The article studied the signal transmission and access technology, designed and developed a part of circuit systems and showed the modular design of the products, the circuit function well in actual system. The study of signal conditioning technology and the a variety of signal conditioning circuit and system designed in this article, has been practical applied in the J- TEXT system, the effect is well, and provided effective protection to experimental operation of the device.