Influential Factors of Measuring Air Pressure Pulse Produced by Passing Trains

The effects of the signal line length, the filter and the sampling frequencies on measuring air pressure pulse were studied in this paper. The results show that when the signal line length of sensor is less than 100 m, its influence on sensor dynamic signal will be less than 1%. It meets the real train test requirement of measuring crossing air pressure pulse. The filter and the sampling frequencies have evident influence on the results of measuring air pressure pulse, so the strain gauge magnifier with the low-pass, and whose filter frequency 100 Hz is supposed to be adopted for measuring crossing air pressure pulse of real train test. It also shows that the measured magnitude of air pressure pulse increases with increasing the sampling frequency until the sampling frequency reaches 1 kHz. In order to reach the factuality of the wave shape and save memory the sampling frequency should be set at 1 kHz.