Research Of Detection Methods Of The Track Circuit FSK Frequency Shift Signal Based On DSP

Along with the rapid development of railway transportation, the running speed of train has improved continuously. It is very important to guarantee the train in the driving range of normal through and safe operation. As a kind of train control signal, the track circuit frequency-shift signal has very close relationship with the safety of the train operation. In order to ensure the train’s safe and effective operation, improving the efficiency of railway transportation, which is necessary to detect the track circuit frequency shift signal on line by a suitable way.Track frequency shift signal is a special kind of track circuit signal, on the basis of making a deep analysis research with the mathematical expression, we understand that the carrier frequency and low frequency modulation frequency of frequency shift keying signal has diversity and frequency value of the characteristic of the large span, and its frequency spectrum has leakage problems. In order to get a good high sampling frequency spectrum value, using the undersampled signal technology on frequency shift keying signal sampling, in the same frequency resolution, greatly reduce the sampling points N, shortening the operation time of the fast Fourier transform of and improving the real-time signal processing. By adding a Tukey-Hanning window, which can make the sidelobe dissolved and eliminate the certain high frequency interference and leakage, with the correction and reduction on the basis of add Tukey-Hanning window, we can get high precision track frequency shift signal parameters. The simulation results show that this method can detect the carrier frequency, low frequency and amplitude of home-made18information railway frequency-shift keying signal and UM-71track circuit frequency-shift signal, carrier frequency error within0.002Hz, low frequency error within0.03Hz and frequency offset error within0.02Hz and amplitude error within0.1%.This paper analyses the TMS3205509with DSP chip as the core, setting up the track frequency shift signal detection system, which mainly consists of two parts, one part is the system hardware structures and peripheral circuit design, and the other part is to finish software design on the basis of the hardware. Using of CCS development tools, writing DSP hardware programs, and sending the results to the PC demonstration platform for analyse of the results. Results show that the parameters are detected by this method can better meet the performance requirements set in this article.