Railway Signal Sending And Improvement Of TVM430 Signal

There are several railway signal systems in our country. For the safe operation, it's necessary to provide a railway signal sending system that can simulate not only all kinds of the present signals but noise. On the other hand, with the acceleration of domestic train, the requirement for the railway signals turn more and more strict, however, it is hard to control the train efficiently because we have not enough bits in our railway signals. Came from France, the TVM430 digital coded signal has more information up to 27 bits, which can meet the need of high-speed train. But slow demodulation is the biggest flaw for TVM430, otherwise, it's expensive for our country to use TVM430 because it hasn't been improved by us. Now it's only used in Qinhuangdao-Shenyang railway line for passenger traffic.For the above problems, the work of this paper composed of two parts:First, design a set of railway signal sending system which can send railway signals on real-time, and provide an interface designed by C++ Builder that is useful for operation. This system is an important part of "Simulation System of Railway Signal Transmission and On-board Cab Signal Receiving" which achieves champion in the national DSP competition organized by TI.Furthermore, this paper focuses on TVM430's technical improvements. We reduce the number of TVM430's low-frequency modulating signals while make sure the same information as TVM430, and search cycle generating polynomial for the improved TVM430 and add parity checking to the important code words. We also redefine frequency and amplitude for low-frequency modulating signals and discuss the phase information, so make the synthesis signal's amplitude have small change.Using TMS320VC33 as a platform we study the sending and demodulating strategy of the improved TVM430, and calculate the decoding speed. It's true that the improved TVM430' demodulating speed is quicker that TVM430 signal.