25Hz Series Track Circuit Receiver Design Based On DSP

The track circuit is a foundation equipment of the train to realize automatic control and long-distance control.The station of out country most use the 25Hz series track circuit.It has the anti-power frequency disturbance ability and the good frequency selectivity and the phase selective.But the 25Hz series track circuit exposes some questions gradually.Because of the design flaw of the dual two relay, it has not been able to meet the need.Along with the promotion of CTCS-2 system, the ZPW-2000 series non-insulation track circuit becomes the main service pattern of the ground.The important link of transformation is superimposes ZPW-2000 on the existing 25Hz series track circuit. Then the dual two relays needed reliable frequency selectivity to makesure that it can not mistake to move the track relay when the shifted electric current is poured into the track coil. It needs improve the performance and structure of the 25Hz sensitive track circuit receiver.In order to make up the flaw of the dual two relays, the related scientific research department had developed micro electron receiver based on the monolithic integrated circuit.Not only had the improvement in the equipment structure and the performance, also complies with the development trend of the current railway signal.On predecessor's foundation,the present paper proposed new thought of applies the digital signal processing technology to the 25Hz series track circuit receiver.The paper has analysised and simulated the FFT algorithm and the digital mutual correlation algorithm.The paper have carried on the detailed introduction about the system main body electric circuit structure, the choice of master control chip,the analog input channel design and the A/D sampling method.The paper also gave the design principle of the clock electric circuit, repositioned the electric circuit, the data-carrier storage, JTAG and various function modules,has completed the hardware circuit design and the software debugging.System software's design has deferenced the modulation principle, has emphasis analyzed the construction of the master routine, the design of A/D sampling interrupt, the design of the main algorithm.Uses the DSP processing chip to process the signal,was quicker than the common monolithic integrated circuit,has enhanced timeliness.Along with DSP and the A/D switch's development,the precision also has the promotion space. Present paper design the double chip integration, the double draught software algorithm to process separately, has enhanced the security and the reliability,has given attention to the efficiency simultaneously.Because of the integrated chip, the volume is small, the weight is light, the power loss is low and it is advantageous for carry, facilitates to maintenance and replacement.Generally speaking,this system have the advanced significance.It is a good way to improve the 25Hz series track circuit receiver.Although the design in this paper is immature, but it has a good application prospect.