| Voice has been constantly knew and researched by people, as a property of things. With combined with the continuous development of electronic technology, voice recognition start to bring convenience and help to people. This thesis is about the development of the railway train near alarm equipment which is based on the dsPIC30F6011A digital signal controller to calculate the audio characteristic value of the wheel-rail voice from the running train. The railway train near alarm equipment is equipped a touch screen which not only has a high computing speed and strong anti-jamming capability but can easy to carry.People can easily judge that is the car or the motorcycle coming from behind when walk on the road. The reason is that people have remembered the voice of car and motorcycle.when hear again, people can recognize which that is. The railway train near alarm equipment is also based on the same principle:firstly, building up the audio characteristic value database; secondly, recognizing and matching wheel-rail voice based on the database; finally, confirming and alarming. But the wheel-rail voice can different depend on the train running in different situation. Therefore, the audio characteristic value we picked can work in different situation such as different load and different Sections. We pick Power Spectrum as the audio characteristic value in this paper. In order to reduce the FFT computation time and meet the short-time requirement, we use assembly language to program. To ensure all program is correct, we simulate all program on the Microchip company’s MBLAP compiler. Some measures also take to ensure hardware circuit is no problem.The wheel-rail voice signal is input the dsPIC30F6011A digital signal controller to build up the audio characteristic value database after being collected, amplified, filtered, analog-to-digital converted. When turned on and put on the rail at construction site, the alarm collects wheel-rail voice and calculates the audio characteristic value and match with the database saved before. If the result measure up to the threshold value, alarm; if not, no alarm and continue to collect, amplify, filter and convert. This alarm uses the touch screen to control and display, which make the operating very easy for workers. |
