Design Of Parameter Detecting System For Frequency-Shift Track Signal Based On DSP

As the train speed rise quickly, the railway capability is being improved year by year, the function of railway is becoming more and more important in our national economy and life. In this case, the people had a higher request to the traffic safety. To guarantee the safety of running train, it is necessary to detect parameters of frequency-shift track signals precisely and timely.This article, by the study of the domestic frequency-shift parameter detecting methods and instruments, proposed a method to detect the frequency-shift parameter, the method was based on DSP processor and ARM upper monitor. The article focus on design of frequency-shift track signal detecting system based on DSP including software and hardware.In algorithm, for the narrow-band characteristic of the track signal we use under-rate sampling instead of Nyquist sampling to reduce the sampling rate. Since the frequency of the modulation signals is low, and it must have higher resolution, we use the ZFFT to detect it, which can satisfy the frequency resolution.On the hardware has mainly completed the circuit design of system based on DSP processor, it includes preprocessing of signal, A/D sampling, power supply module, clock and reset module, FLASH ROM, JTAG testing interface, and the communication interface HPI. At the last we program the parameter detecting methods for frequency-shift track signal with C language and assembly language base on CCS, then we realize it on the DSP chip. Experiments shows that it can detect the carrier frequency and the low frequency of modulation signals.The overall system made use of excellences of DSP and ARM, the excellences include the high precision and speed of DSP processing digital signal, the full real-time operation and high intellectualized degree of ARM.