Shift The Frequency Of The Signal Detection Method Research And Application

With the improvement of the velocity of the train, more information frequency-shift signal in automatic blocking system is widely used in automatic control system of the block region. The reliability of the track influences the safe operation of the railway, the flux capacity of the track and the punctual arrival of the train. Especially after the improvement of the velocity of the train for several times, the railway is in the direction of heavy load and high speed. It is important to check the train circuit regularly to ensure it to work well so that the train can be operated safely and punctually. Study on the detection of the frequency-shift in both the time domain and the frequency domain is provided in this paper.In this paper, the characters of the railway frequency-shift signal is analyzed; according its characters, the measuring width in time domain is given and according this method a system of the single-chip which is low power and can work with wide voltage is given: the measuring scope of the RMS value is changed automatically by the chip Max134 with the help of the CPU; the zero point is captured by the time2 of the chip 8052, and then a series of period of the signal is found, the frequency-shift of the signal such as the upper frequency-parameter, the middle frequency, the lower frequency and the low frequency are worked out by analyzing these periods.The detection on the frequency-shift signal in time domain have more time effect. But its capacity of anti-interference is bad. Sometimes this way cannot satisfy the need of the railway system. According to the characters of the frequency-shift signal, Fast Fourier transformation and wavelet analysis in the frequency domain is studied to detect the frequency-shift signal, the computer emulation of these two ways is given, the conclusion that the detection in the frequency domain is stronger is drawn by study.